Appendix A — Glossary

Every term is defined where the course first teaches it. This page collects those definitions. Use the search box (top left) or your browser’s find for quick lookups, and follow the chapter link for the full picture.

10 personnel: One running back, no tight end and four wide receivers. A spread grouping that is rare in the NFL and common in college. Taught in Personnel: Who’s on the Field Before Anything Else.
10-second runoff: Ten seconds taken off the game clock as a penalty when, after the two-minute warning of either half, the offense stops the clock illegally (a foul, intentional grounding, an illegal pass) or a replay reversal turns a stopped clock into a running one. The offense can avoid a foul-caused runoff by using a timeout, and either half can end on one. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
11 personnel: One running back, one tight end and three wide receivers. The NFL’s most common grouping, used on roughly 60% of plays in 2016-2025. Taught in Personnel: Who’s on the Field Before Anything Else.
12 personnel: One running back, two tight ends and two wide receivers. The NFL’s second most common grouping and close to a coin flip between run and pass. Taught in Personnel: Who’s on the Field Before Anything Else.
13 personnel: One running back, three tight ends and one wide receiver. A heavy grouping for short yardage and the running game. Taught in Personnel: Who’s on the Field Before Anything Else.
2-4-5: A nickel front with two down linemen, four linebackers and five defensive backs: usually a 3-4 team’s nickel, with the nose off the field and the two outside linebackers on the edges, so it looks like a four-man line. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
2-Man: A coverage with two deep safeties, each guarding a deep half, and five defenders playing man-to-man underneath them, usually in trail technique with inside leverage because their help is over the top. Usually rushes four. Taught in Cover 2 and Tampa 2.
2-read: See Palms.
21 personnel: Two running backs (usually a fullback and a tailback), one tight end and two wide receivers. The classic I-formation grouping. Taught in Personnel: Who’s on the Field Before Anything Else.
22 personnel: Two running backs, two tight ends and one wide receiver. One of the heaviest common groupings, used mostly to run. Taught in Personnel: Who’s on the Field Before Anything Else.
2x2: A formation with two receivers on each side of the ball (counting tight ends and backs who line up outside the tackles). Balanced, so it doesn’t tell the defense which side the play is going to. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
3-3-5: A nickel defense with three down linemen, three linebackers and five defensive backs. As an NFL front call it means a five-man line in nickel (three interior linemen, two stand-up edges, one linebacker), the tite of a 3-4 team’s nickel; as a roster count it usually just means a four-man line with one edge listed as an end and the other as a linebacker; the college 3-3-5 stack is a different defense again. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
3-3-5 stack: A college defense with three down linemen, three linebackers stacked directly behind them and five defensive backs, two of them hybrid safety-linebackers who align outside the box; built to put speed on the field against spread offenses and to hide which of the stacked players will rush. Taught in The College Laboratory: Wing-T, Wishbone, Air Raid, Spread Option, and the RPO.
3-4: A base defense with three defensive linemen and four linebackers, plus four defensive backs. The two outside linebackers usually rush the passer like defensive ends. Taught in A First Look at Defense.
3-4 Okie: The classic 3-4 alignment, named for Bud Wilkinson’s Oklahoma 5-2: a nose head-up on the center, a defensive end on each offensive tackle (head-up in a 4 or outside in a 5), a stand-up outside linebacker at each end of the line and two inside linebackers behind the guards. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
3-technique: A defensive tackle lined up on the outside shoulder of a guard, in the B gap; in four-man fronts the position’s name, usually the line’s best interior pass rusher. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
3-under 3-deep pressure: See Fire zone.
3x1: A formation with three receivers on one side of the ball and one on the other. It overloads one side and isolates the single receiver on the other. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
3x1 check (solo / stubbie): A pre-planned adjustment of a two-high coverage to a 3x1 (trips) formation. In one common version of Solo the backside corner plays the lone receiver by himself and a linebacker takes #3 deep, freeing the backside safety; in Stubbie four defenders handle the three trips receivers and the backside safety stays home with the corner. Names and details vary by staff (some playbooks use ‘Solo’ for what this book calls poach). Taught in Disguise, Rotation, and Split-Field Coverage.
3x2: See Empty.
4-2-5: A nickel front with four down linemen, two linebackers and five defensive backs; the modern NFL’s most common way to line up against three receivers. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
4-3: A base defense with four defensive linemen and three linebackers, plus four defensive backs. Taught in A First Look at Defense.
4-3 Over: An even front shifted toward the offense’s strength (usually the tight end): the 3-technique and one end on the strong side, the 1-technique shaded to the weak side of the center, the other end on the weak side, and the Sam linebacker off the ball outside the tight end. The guard left without a lineman on him is the weak-side guard. Taught in Even Fronts: 4-3 Over, Under, Wide-9, and the 46 Bear.
4-3 Under: An even front shifted away from the offense’s strength: the 3-technique on the weak side, the nose shaded to the strong side of the center, a 5-technique end on the strong side and the Sam linebacker on the line outside the tight end. The guard left without a lineman on him is the strong-side guard, with the Mike over him. Often described as a 4-3 with 3-4 personnel. Taught in Even Fronts: 4-3 Over, Under, Wide-9, and the 46 Bear.
46 defense: Buddy Ryan’s eight-man front of the 1980s Chicago Bears, named for safety Doug Plank’s jersey number, not for a count of players: a bear front (the center and both guards covered), both outside linebackers on the tight end’s side, the strong safety in the box as a linebacker, and usually man coverage and a blitz behind it. Taught in Even Fronts: 4-3 Over, Under, Wide-9, and the 46 Bear.
4i-technique: A defensive lineman lined up on the inside shoulder of an offensive tackle, in the B gap; common for the ends of three-man fronts. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
5-technique: A defensive lineman lined up on the outside shoulder of an offensive tackle, in the C gap; in 3-4 defenses the usual name for the defensive end position. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
53 defense: Bill Arnsparger’s package for the early-1970s Miami Dolphins, named for linebacker Bob Matheson’s jersey number: Matheson lined up at the end of the line and either rushed like a fourth defensive lineman or dropped like a fourth linebacker, so the same eleven players could be a 4-3 or a 3-4 from one snap to the next. Usually named as an NFL ancestor of the 3-4. Taught in 1978 and the Passing Revolution (1978–1999).
9 route: See Go route.

A

A-gap mug: See Double A-gap mug.
Accept / decline (penalty): The fouled team’s choice after a foul during a play: accept the penalty (the play’s result is usually wiped out and the yardage enforced) or decline it and keep the result of the play as though no foul had happened. Taught in Contact Rules and Penalties as Strategy.
Ace formation: A singleback formation with two tight ends, one on each side of the line, and two wide receivers (12 personnel), balanced so the defense cannot tell which side is strong. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Adjusted net yards per attempt: See ANY/A.
aDOT: Average depth of target: the average air yards per pass thrown by a quarterback, or per target for a receiver. How far downfield, on average, the ball is aimed. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
ADP: Average draft position: the average pick at which a player is taken across many fantasy drafts. It works as the market price of a player; a pick has value when the player finishes better than the slot he cost. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
AFL: The American Football League (1960–1969), the rival league that played a more wide-open passing game, introduced the two-point conversion and won two of the four AFL–NFL Super Bowls before merging with the NFL (agreement 1966, complete 1970). Its ten teams became the core of today’s AFC. Taught in From the Single Wing to the 1970s Scoring Drought (1906–1977).
Aiming point: The spot a running back’s first steps point at on a designed run, such as the play-side guard’s outside hip on inside zone or the tight end’s outside leg on outside zone. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Air Coryell: The vertical passing offense of Don Coryell’s San Diego Chargers (1978–1986) and its descendants, best known for calling the receivers’ routes with numbers from a route tree (the digit system). Taught in Offensive Systems and Play-Calling Languages.
Air Raid: The shotgun passing offense of Hal Mumme and Mike Leach (Iowa Wesleyan, Valdosta State, Kentucky, Texas Tech): a small menu of pass concepts such as mesh and Y-cross, called with one word or a hand signal, often without a huddle, and practised endlessly. Taught in Offensive Systems and Play-Calling Languages.
Air yards: How far past the line of scrimmage a pass travels in the air, to the spot where it is caught (or where the target was when it fell incomplete). Throws behind the line have negative air yards. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Air-yards share: A player’s share of his team’s air yards: the distance past the line of scrimmage that passes thrown to him travel in the air, summed over the season and divided by the same total for the whole team. It measures how much of the team’s downfield passing is aimed at him. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Alert: A pre-planned exception to the called play: if the quarterback sees a specific look before the snap (most often a single deep safety and a favourable one-on-one matchup outside), he throws to the alert receiver first, usually a deep route, and otherwise runs the play as called. Names and rules vary by team. Taught in What Beats What: Reading Coverage and Pass Concepts Versus Coverages.
Alignment: Where a player lines up before the snap on a particular play: his spot, depth and position relative to the ball and to the other players. Taught in The Twenty-Two.
All-22: Game film shot from high above the sideline and zoomed out so that all 22 players stay in the frame for the whole play, with no cut-aways. The standard view for studying a game. Taught in How to Watch a Broadcast Like You Mean It.
Alley player: The defender, usually a safety or a linebacker, who fills the alley: the lane between the force player and the last defender in the box, where a run that has bounced outside the box but not outside the force has to go. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
American Football League: See AFL.
Analytics staff: Staff who turn data into decisions. On game day, a game-management specialist advises the head coach on fourth downs, two-point tries, timeouts and challenges. Taught in What a Play Really Is.
Anchor: A pass blocker’s ability to stop being pushed backward by a power rush: hips down, base wide, feet regained, so the pocket does not collapse into the quarterback. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Angle (line movement): A called movement in which a defensive lineman steps at about 45 degrees into the gap beside him at the snap, moving over one gap while still getting upfield; a shorter, more penetrating move than a slant, often by one or two linemen rather than the whole line. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Angle route: A running back’s route that starts toward the flat, as if on a swing or flat route, then snaps back inside and upfield under the linebackers. Built to beat a linebacker covering the back in man coverage. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Anticipation throw: A pass released before the receiver is open, usually before he makes his break, aimed at the spot where the window between defenders will be when the ball arrives. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
ANY/A: Adjusted net yards per attempt: passing yards plus 20 per touchdown pass, minus 45 per interception and minus yards lost on sacks, divided by pass attempts plus sacks. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Apex: An alignment halfway between the last man in the box (a tackle or tight end) and a slot receiver, a few yards off the ball, from which a defender can help against the run or cover the receiver. Taught in A First Look at Defense.
Apex alignment: See Apex.
Arc block: A tight end or H-back’s release around the outside of an unblocked end to block the next defender out (an overhang or safety), usually paired with a quarterback read. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Assignment: A player’s job on a particular play: whom he blocks, which route he runs, which gap he fills or which receiver or area he covers. Taught in The Twenty-Two.
Assisting the runner: The NFL rule on teammates helping a ball carrier forward. Since the mid-2000s (2005 or 2006; accounts differ) teammates may push the runner; pulling him (grabbing and hauling him forward) is still a 10-yard foul. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Audible: Changing the play at the line of scrimmage by voice or hand signal after seeing how the defense has lined up. The umbrella term for checks, kill calls and check-with-me. Taught in The Pre-Snap Phase.
Average depth of target: See aDOT.
Average draft position: See ADP.

B

Back judge: The deepest official, about 25 yards past the line in the middle of the field. He watches the tight end and inside receivers, the deep middle and the end line, and stands under the other upright on field goals. Taught in Officiating, Replay, and the Rules of the Ball.
Back-shoulder throw: A pass deliberately thrown short and behind a receiver who is running a vertical or fade route, to his back (usually outside) shoulder, so he stops and turns to catch it while the defender running with him is carried past. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Backed up: Snapping the ball inside your own 10-yard line (minus 1 to minus 10 on a call sheet). A sack or a holding foul in your own end zone is a safety, and even a good drive has 90-plus yards to go, so offenses call their most careful plays here. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
Backside cut-off: The job of the linemen away from the play on a zone run: get in front of the defenders on their side so those defenders cannot chase the play from behind. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Backward pass: Any pass that is not forward, including one thrown straight across the field parallel to the line. Anyone may throw one at any time, from anywhere; if it hits the ground the ball is still live, so either team may recover it, and advance it. Taught in Officiating, Replay, and the Rules of the Ball.
Bail: A cornerback technique: at the snap, turn the hips and run to a deep landmark instead of backpedalling. Used from off alignments every week; from a press look (‘press-bail’) it also makes a zone coverage look like man before the snap. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Bang-bend-bounce: The zone runner’s three choices after pressing the aiming point: hit the designed gap (bang), cut back against the flow behind the blocks (bend), or take it outside (bounce). Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Banjo: A two-defender rule for two receivers who line up close together (a stack, a bunch or a tight split): instead of each defender locking onto one man, they decide at the release, usually with the outside defender taking the first receiver to break outside and the inside defender the first to break inside (an in/out banjo; some teams split them short/deep instead), so neither has to fight through traffic. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Base block: See Drive block.
Base defense: A defense’s traditional package: four defensive backs plus seven front players (a 4-3 or a 3-4), built for offenses with two backs or two tight ends. In the modern NFL it is no longer the package teams use most. Taught in A First Look at Defense.
Base play: One of the handful of plays an offense (or a defense) builds itself around and calls most often: the play it wants to be good at whatever the opponent does, and the one its other plays are designed to protect. Taught in Constraint Theory: How Plays Talk to Each Other.
Bash: Short for ‘back away’: a zone tag in which the running back runs away from the line’s zone flow while the quarterback reads the end man and can keep the ball on the inside-zone track. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Bear front: A front that covers the center and both guards (a 0-technique nose and a 3-technique on each guard), so no interior offensive lineman is free to double-team or climb to a linebacker. The line of the 46 defense; now a situational front, used near the goal line, against heavy formations and on early downs against zone-running teams. Taught in Even Fronts: 4-3 Over, Under, Wide-9, and the 46 Bear.
Bear pressure: A blitz from a bear front, in which the center and both guards are covered by defensive linemen. No interior blocker is free to help, so every lineman is locked in a one-on-one and any extra rusher from the second level has to be picked up by a back. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Big Data Bowl: The NFL’s annual public analytics competition, held since 2019: entrants get a release of player-tracking data and build new metrics or models around a theme the league sets. Taught in Tracking Data and the Big Data Bowl.
Big nickel: A nickel package whose fifth defensive back is a third safety rather than a cornerback, giving more size against the run and against tight ends. Taught in A First Look at Defense.
Big-on-big: See Man protection.
Blind-side tackle: The offensive tackle who protects the side a quarterback cannot see as he sets to throw: the left tackle for a right-handed passer, the right tackle for a left-hander. Since the 1980s teams have treated it as the premium position on the offensive line. Taught in 1978 and the Passing Revolution (1978–1999).
Blitz: A pass rush with five or more rushers, so that more defenders attack the quarterback than the usual four. The extra rusher is usually a linebacker or a defensive back. Taught in A First Look at Defense.
Block in the back: Pushing or blocking an opponent from behind above the waist when he is not the ball carrier. The NFL’s name for it is an illegal block above the waist; ten yards. The same block below the waist is clipping, fifteen yards. Taught in Contact Rules and Penalties as Strategy.
BOB: See Man protection.
Booth review: A replay review started by the replay official in the stadium (or the officiating command center in New York), not by a coach. It covers every scoring play, every turnover, every try, every ruling that the offense came up short on fourth down, and reviewable plays after the two-minute warning of each half and in overtime. A coach may not challenge these. Taught in Officiating, Replay, and the Rules of the Ball.
Bootleg: A play-action pass in which the quarterback fakes a run one way, then rolls out the other way with the ball, away from where the run fake sent the defense, toward receivers set at short, medium and deep levels on that side. Taught in Play-Action, Bootlegs, and Screens.
Bounce kick: See Squib kick.
Boundary side: When the ball is on a hash, the side nearer the sideline, with less room. Taught in The Game in Fifteen Minutes.
Box: The area near the ball where the run is defended: roughly from just outside one end of the offensive line to just outside the other (including an attached tight end), and about 5 to 7 yards deep. Taught in A First Look at Defense.
Box count: The number of defenders in the box at the snap. Compared with the number of blockers the offense has, it tells you how well the defense is set to stop a run. Taught in A First Look at Defense.
Box technique: A run-fit technique in which a defender meets a kick-out or pulling blocker with his outside arm free and squeezes him inside, shrinking the hole and keeping the ball inside him, toward the linebackers. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Bracket: Two defenders on one receiver, one on each side of him: underneath and over the top (under-over) or inside and outside (in-out), so that whichever way he breaks, a defender is already there. The usual way to take away a star. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Break-even conversion rate: The chance of converting a fourth down at which going for it and the best kicking option give the same win probability. If you believe the play converts more often than that, the numbers say go. Taught in Win Probability and Decision Analysis: Fourth Downs, Two-Pointers, Timeouts.
Brier score: The average, over a set of probability forecasts, of the squared gap between the stated probability and what happened (1 if it came true, 0 if not). Lower is better: 0 is perfect, saying 50% every time scores 0.25, and a confident miss costs far more than a timid one. Named for the meteorologist Glenn Brier, who proposed it in 1950. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
Brier skill score: One minus the ratio of your Brier score to a reference forecaster’s on the same events: 0 means no better than the reference, positive means better, and 1 would be perfect. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
Bubble RPO: An RPO that pairs a run with a bubble screen to a slot receiver: the quarterback hands off if the box is even, or throws the bubble if the defense has taken a defender from outside to stand in the box. Taught in Run-Pass Options: Plays That Are Two Plays.
Bubble screen: A screen to an inside receiver who drifts back and out toward the sideline (the ‘bubble’) and catches the ball on the move, behind blocks from the receivers outside him. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Buck sweep: The signature play of the Wing-T: the halfback sweeps toward the wingback’s side behind both guards, who pull (one kicks out the end man, the other turns up inside him), while the tight end and wingback block down and the fullback fakes a plunge (‘buck’) up the middle. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Bull rush: A pass rush straight through the blocker: hands inside on his chest, legs driving, pushing him backward into the quarterback instead of trying to get around him. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Bump (defensive adjustment): Defenders sliding one spot toward the motion instead of following it, so nobody crosses the formation. It is the usual zone answer, but man defenses slide too (an exchange), so a bump alone does not prove zone: look at where the slid defenders end up. Taught in Motion and Shifts as Weapons.
Bunch: Three receivers clustered in a tight triangle on one side, usually within two or three yards of each other, with one of them on the line and two just off it. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Buzz rotation: A Cover 3 rotation in which a safety comes down to the hook-curl area, inside, and the linebacker or nickel back already aligned outside on that side takes the curl-flat. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.

C

Cadence: The words and rhythm the quarterback uses at the line, and the agreed signal on which the center snaps the ball. The offense knows when the ball will move; the defense has to react to it. Taught in The Pre-Snap Phase.
Calibration: How closely stated confidences match how often things come true: a well-calibrated forecaster’s 70% calls come true about 70% of the time. Shown on a calibration plot (stated confidence against the actual hit rate, with the diagonal as perfect); points below the diagonal mean overconfidence, points above it underconfidence. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
Call sheet: The play-caller’s game-day menu: that week’s plays sorted by situation (down and distance, field zone, clock) on one or two laminated pages. Taught in What a Play Really Is.
Cap hit: The amount a player’s contract counts against his team’s salary cap in one league year: his base salary, the year’s share of his signing bonus, and any roster, workout or incentive bonuses counted that year. It is an accounting number, not the cash he is paid that year. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Cat blitz: See Nickel blitz.
Catch (completed pass): Under the rule rewritten in 2018, a player catches a forward pass when he (1) secures control of the ball in his hands or arms before it touches the ground, (2) touches the ground in bounds with both feet or another body part other than his hands, and then (3) makes an act common to the game, such as tucking the ball, turning upfield or reaching for the line, or keeps control long enough to do so. The same test decides an interception. Taught in Officiating, Replay, and the Rules of the Ball.
Center: The offensive lineman in the middle of the line who snaps the ball to the quarterback and then blocks; he usually also identifies which defender the blocking scheme counts from. Taught in The Twenty-Two.
Chains: See The sticks.
Charting: See Game charting.
Check: A pre-planned change built into a call: ‘if the defense shows this, we switch to that.’ Offenses and defenses both use them. Taught in The Pre-Snap Phase.
Check-release: A back’s or tight end’s pass-protection rule: watch an assigned defender at the snap; if he rushes, block him; if he does not, release into a pass route. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Check-with-me: A system in which the play is not final in the huddle. The quarterback picks it at the line from a short menu after reading the defense. Taught in The Pre-Snap Phase.
Checkdown: The short, safe throw at the end of a progression, usually to a running back or tight end underneath the coverage, taken when the deeper reads are covered. It trades a chance at a big gain for a near-certain small one. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
Chip: A quick hit by a tight end or back on a pass rusher, usually an edge rusher, to slow him down and help the tackle, delivered on the way out into a pass route; a back chips only after checking that no blitzer is his (check, chip, release). Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Choice route: See Option route.
Chop block: Two blockers taking on the same defender, one high and one low at the thigh or below, together or one right after the other. Banned in every situation in the NFL since 2016; fifteen yards. Taught in Contact Rules and Penalties as Strategy.
Chuck rule: Any of the rules limiting how a defender may hit or shove (chuck) a receiver who is running his route. From 1974, only once after the receiver was 3 yards past the line; from 1977, only once in all; since 1978, only within 5 yards of the line (the Mel Blount rule). Taught in From the Single Wing to the 1970s Scoring Drought (1906–1977).
Climbing the pocket: The quarterback stepping forward into the pocket, between his interior linemen, as the edge rushers are pushed past him, so that he can keep reading and throw from a clean spot instead of drifting back into the rush. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
Cloud rotation: A Cover 3 rotation in which the cornerback on one side stays shallow and plays the flat (‘c’ for cloud and for corner), and the safety on that side runs to the deep outside third behind him. It often starts from a two-high look and resembles Cover 2 on that side before the snap. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.
Coach’s challenge: A head coach’s request, made by throwing a red flag before the next snap, for a replay review of a reviewable ruling. Each team gets two per game, plus a third if either of the first two succeeds (since 2024); a team must have a timeout to challenge and loses it if the challenge fails. Not allowed inside the final two minutes of a half or in overtime, where the booth reviews instead. Taught in Officiating, Replay, and the Rules of the Ball.
Coaches film: The video a team’s staff studies: every snap shown twice, once from the high wide sideline angle (the All-22) and once from a high end-zone angle, with no replays, close-ups or graphics. Fans can buy access to it. Taught in How to Watch a Broadcast Like You Mean It.
Coaching booth: The glassed-in coaches’ room at press-box level where part of the staff (often one coordinator, quality control coaches and analysts) watches the game from above, sees all 22 players at once, charts what the opponent is doing and relays it to the sideline by headset. Taught in In-Game Adjustments, Tempo, and the Sideline Battle.
Coaching tree: The family of coaches descended from one head coach, traced through who worked on whose staff: a branch runs from a head coach or coordinator to an assistant who later led a staff of his own. Because most coaches work for several bosses, one coach can sit on several branches. A tree records where coaches learned, not that they run the same plays. Taught in Case Study: Bill Walsh’s 49ers and the West Coast Offense.
Coffin-corner punt: A punt aimed to go out of bounds just short of the goal line, near the corner of the field, so the receiving team must start its drive deep in its own territory without a chance to return the kick. Taught in Field Goals, Extra Points, and the Punting Game.
Combine: See NFL Scouting Combine.
Combo block: Two adjacent linemen blocking one defensive lineman together to move him, while watching the linebacker behind; when the linebacker commits, one of them comes off (‘climbs’) to block him. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Combo coverage: Any coverage in which two or more defenders share two or more receivers and decide who takes whom by how the routes declare after the snap (a banjo is the simplest), or which mixes man rules and zone rules on the same snap. Charters also use the word for a play that fits no single coverage label. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Comeback: A route that sells a deep route for about 15 yards, then stops and comes back toward the sideline and the quarterback (the 3 in many route trees). Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Coming out: The zone just beyond backed up, roughly your own 10 to your own 25 (minus 10 to minus 25): the offense wants its first first down, to get the ball away from its own goal line and give its punter room. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
Compensatory pick: An extra draft pick, at the end of rounds 3 to 7, awarded to a team that lost more or better unrestricted free agents than it signed the year before. The league’s formula weighs each player’s new salary, playing time and honors; at most 32 are awarded a year. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Completion percentage over expected: See CPOE.
Compressed field: The shrunken playing area near the goal line: the end line, at most 10 yards behind the goal line, caps how deep routes and zones can go, so the defense has far less grass to protect and defenders stand closer together. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Concept-based terminology: A play-calling language in which one word names a whole route combination (a concept) rather than each receiver’s route, so the call stays short and the concept can be run from any formation. Erhardt-Perkins is the best-known example. Taught in Offensive Systems and Play-Calling Languages.
Condensed formation: A formation in which the receivers line up close to the offensive line (reduced or tight splits) instead of out near the sidelines, to set up crack blocks, two-way gos and rubs, and to make runs and passes look the same. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Conflict defender: A defender who is responsible for two things at once (two receivers in his area, or a run gap and a pass zone), so that whatever he does leaves one of them open. Pass plays and RPOs are built around him. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Constraint play: A play whose main job is to punish a defense for over-playing the base play. It works best exactly when the defense cheats to stop the base play, so its threat keeps the defense honest; called too often, it stops working. Taught in Constraint Theory: How Plays Talk to Each Other.
Contain: A defender’s rule to keep the ball carrier, especially a quarterback on a scramble, bootleg or keeper, from getting outside him; for edge rushers on a pass, not rushing past the quarterback’s depth and opening an escape lane. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Contested catch: A catch, or attempted catch, made with a defender close enough to touch or fight for the ball at the catch point. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Corner rotation: See Cloud rotation.
Corner route: A route that pushes upfield 10–12 yards, then angles toward the sideline and the far corner of the field or end zone (the 7 in many route trees). Also called a flag route. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Cornerback: A defensive back who lines up across from the wide receivers, usually near the sideline, and covers them on passing plays. Taught in The Twenty-Two.
Counter: A gap-scheme run that starts with the running back stepping away from the play, then pulls two backside blockers the other way: classically the guard, who kicks out the end man, and the tackle, who swings around the kick-out and leads through the hole (GT counter: guard and tackle). Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Counter trey: See Counter.
Cover 0: Man coverage with no deep safety: every eligible receiver has a defender on him and no one is left to help over the top. The defenders without a man usually rush (most often a six- or seven-man blitz), though some versions keep one of them free underneath. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Cover 0 blitz: A blitz played with Cover 0 behind it: usually six or seven rushers, man coverage on every eligible receiver and no deep safety, built so that the protection cannot block everyone and the quarterback must throw before the free man arrives. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Cover 1: Man coverage with one deep safety in the middle of the field: every eligible receiver has a defender on him, the free safety plays the deep middle as help for all of them, and the defense usually has one more defender left over to rush, spy or sit in the middle. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Cover 1 blitz: A blitz played with Cover 1 behind it: usually five or six rushers, man coverage on every eligible receiver, and one deep safety in the middle of the field as help for all of them. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Cover 2: A two-deep zone coverage: two safeties each guard a deep half of the field, and five defenders guard the short zones underneath them, usually the two cornerbacks in the flats and three linebackers (or two linebackers and a nickel back) in the two hook-curl zones and the middle hole. Taught in Cover 2 and Tampa 2.
Cover 3: A zone coverage with three deep defenders, each guarding a third of the field’s width (usually the two cornerbacks outside and one safety in the middle), and four underneath zone defenders. A one-high, middle-of-the-field-closed coverage, and the most common zone in the NFL. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.
Cover 3 match: Cover 3 played with pattern-matching rules: the defenders start in their zones and then pick up receivers by their routes (the corners carry the outside receivers deep, the seam-flat defenders carry the slot receivers up the seams), so four vertical routes meet four defenders instead of three. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.
Cover 4: See Quarters.
Cover 5: See 2-Man.
Cover 6: A split-field coverage that plays quarters on one half of the field and Cover 2 on the other (quarter-quarter-half): usually quarters toward the formation’s strength or the wide side, and a squat corner with a deep-half safety on the other side. Taught in Quarters and the Two-High Match Family: Cover 4, Cover 6, Palms.
Cover 7 (match family): A label whose meaning depends on the staff. In Nick Saban’s vocabulary it names a split-field, quarters-based pattern-match family built from a separate call for each side; other teams use ‘Cover 7’ for different coverages. Taught in Disguise, Rotation, and Split-Field Coverage.
Cover 8: A rarely used number with no standard meaning. In Vic Fangio’s vocabulary it is a split-field coverage, quarters on one side and Cover 2 on the other (what most teams call Cover 6); other staffs use 8 for other calls. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Cover 9: A number with several meanings: a Cover 3 in which the safety away from the offense’s strength comes down (weak rotation) on some staffs, Cover 3 match or a split-field call on others. The FTN charting in nflverse has labelled plays COVER_9 since 2023. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Coverage beater: A pass concept whose routes are arranged to attack the known weak spots of a particular coverage (for example smash against Cover 2, flood against Cover 3), so that if the defense plays that coverage, at least one receiver should come open. It raises the odds against that coverage; it does not guarantee a completion, and it is usually worse against others. Taught in What Beats What: Reading Coverage and Pass Concepts Versus Coverages.
Coverage charting: Labelling each pass play with the coverage the defense played after the snap (Cover 1, Cover 3, quarters and so on, and whether it was man or zone), done by analysts watching film. The labels are informed judgements, not the defense’s own call sheet, and different charting sources code them differently. Taught in Tendencies: PROE, Personnel, Motion, and Coverage from Charting Data.
Coverage numbering (Cover 0-9): The naming convention behind ‘Cover 0’ to ‘Cover 9’. Through Cover 4 the number usually counts the deep defenders; from 5 up the numbers are names, and their meaning differs from staff to staff. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Covered / uncovered lineman: An offensive lineman is covered when a defensive lineman is lined up on him (head-up or on a shoulder) and uncovered when none is, so the nearest defender in front of him is a linebacker. Uncovered linemen are the ones free to double-team and to climb to the linebackers. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Covered receiver: A player on the line of scrimmage who is not at either end of it, because a teammate is also on the line outside him. On that play he may not catch a forward pass, whatever his position or jersey number. Taught in Formation Rules and the Language of Alignment.
CPOE: Completion percentage over expected: a passer’s completion rate minus the rate a model expects from how difficult his throws were (depth, location, down and distance, and in some models how open the receiver was). Positive means he completed more passes than throws like his usually produce. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
Crack block: A block by a player lined up outside the play, usually a wide receiver or wingback, who comes back toward the ball and hits a defender (often a linebacker or safety watching the ball) from the side. In the NFL it must be above the waist and not to the head or neck. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Crack-and-replace: The pairing of blocks on a perimeter run in which a receiver leaves the defender he would normally block (usually the cornerback) to crack inside, and a pulling lineman replaces him on that defender. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Crack-toss: A toss sweep on which a receiver lined up outside the play blocks back inside (a crack block) on the defender responsible for the edge, while a pulling lineman replaces him on the cornerback. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Creeper: See Simulated pressure.
Cross-chop: A hand move against a blocker’s punch: the rusher swings his outside arm across his own body and chops down on the blocker’s hands or forearms, usually followed by a rip or dip, so the blocker never gets a grip. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Curl route: See Hitch.
Curl zone: The intermediate area between the hash marks and the numbers, centred about 10 to 12 yards deep, where curls, deep hitches and in-breaking routes from wide receivers arrive. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Curl-flat: A concept pairing a curl at 10–12 yards with a flat route underneath, often with a third receiver settling in a hook route inside: a high-low read of the defender covering the curl and the flat. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Curl-flat defender: The outside underneath defender on one side of a zone coverage (in Cover 3, one on each side). He drops toward the curl zone under the outside receiver and breaks to the flat when the ball or a receiver goes there: one player guarding two areas. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.
Cushion: The distance, in yards of depth, between a defender and the receiver he is covering. A big cushion protects against the deep ball and concedes the short throw. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Cut block: A legal block aimed at a defender’s thighs or below, from the front, to put him on the ground; restricted by rule to protect knees and banned when combined with a high block (a chop block). Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Cut-off block: A backside block in which the lineman steps play-side to get between a defender and the play, so the defender cannot chase it; he does not need to move the man, only stay in his path. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Cutback: A ball carrier’s cut against the flow of the play, back toward the side the line stepped away from, into a lane created by defenders over-running the play. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.

D

Dagger: A concept in which the inside receiver runs straight up the seam to pull the underneath and deep defenders away, and the outside receiver runs a deep dig (15–18 yards) into the space they leave. Built to beat two-high coverages. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
DC: See Defensive coordinator.
Dead money: Cap charges for players no longer on the roster: when a team releases or trades a player, every year of his signing bonus not yet counted (and any guaranteed salary it still owes) hits the cap at once. It pays for no one on the field. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Deep half: One of two deep zones, each half the field’s width (about 27 yards), guarded by a safety in Cover 2 and its relatives. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Deep quarter: One of four deep zones, each about 13 yards wide, guarded by the two cornerbacks and the two safeties in quarters (Cover 4). Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Deep third: One of three deep zones, each a third of the field’s width (about 18 yards), guarded by the two cornerbacks and a deep middle safety in Cover 3. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Defenseless player: A player the rules treat as unable to protect himself (a passer throwing, a receiver trying to catch a pass, a player on the ground, a kicker or returner during the kick, and others) and so protect from forcible hits to the head and neck and from launching. Taught in Contact Rules and Penalties as Strategy.
Defensive coordinator: The assistant in charge of the defense’s game plan. Usually, but not always, the defense’s play-caller. Taught in What a Play Really Is.
Defensive end: A defensive lineman who lines up at or near the end of the defensive line, outside the offensive tackles; his main jobs are rushing the passer and keeping runs from getting outside. Taught in The Twenty-Two.
Defensive holding: A defender grabbing, hooking or otherwise restricting an eligible receiver (or any offensive player who is not the ball carrier) before a pass is thrown. Five yards and an automatic first down. Taught in Contact Rules and Penalties as Strategy.
Defensive package: The group of eleven defenders on the field for a snap, named mostly by how many defensive backs it has (base, nickel, dime and so on) and chosen mainly to match the offense’s personnel. Taught in A First Look at Defense.
Defensive pass interference: Contact by a defender, after the ball is thrown and more than one yard past the line of scrimmage, that significantly hinders a receiver’s chance to catch a catchable pass. In the NFL it is a spot foul: an automatic first down at the spot of the foul, or at the 1-yard line if the foul is in the end zone. Taught in Contact Rules and Penalties as Strategy.
Defensive tackle: A defensive lineman who lines up inside, across from the guards or center, to clog the middle against the run and push the pocket on passes. In a four-man line one tackle usually absorbs double-teams over the center and the other (the 3-technique) shoots a gap and rushes the passer. Taught in The Twenty-Two.
Delay of game: A five-yard penalty, almost always on the offense, for not snapping the ball before the play clock reaches zero. Taught in What a Play Really Is.
Dig: A route that runs upfield and then breaks flat across toward the middle of the field, usually 10–15 yards deep (the 6 in many route trees). Shallower versions are often just called in routes. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Digit system (route numbering): Calling pass routes by their numbers in the route tree, one digit per receiver in a fixed order (classically the X receiver, the tight end, then Z), so ‘896’ sends three receivers on an 8, a 9 and a 6. Other players get their routes by name. Taught in Offensive Systems and Play-Calling Languages.
Dime: A package with six defensive backs, usually with only one linebacker, for obvious passing downs. A dime is worth two nickels. Taught in A First Look at Defense.
Disguise: Lining up in a way that hides or misrepresents the coverage (or pressure) the defense will actually play, so the quarterback’s pre-snap read is wrong or useless. Taught in Disguise, Rotation, and Split-Field Coverage.
Dive: The inside runner on an option play, usually a fullback or B-back driving straight at a guard or tackle; the first of the triple option’s three threats. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Dollar: See Quarter (package).
Double A-gap mug: Two defenders (usually linebackers) standing in both A gaps, on either side of the center, threatening to blitz before the snap. From that one look the defense can send both, one or neither, which attacks the protection’s count and its Mike identification. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Double move: A route that fakes a common short route (a slant, a hitch, an out) to get the defender to jump it, then breaks a second time, usually deep. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Double slants: Two receivers on the same side both running slants, the inside one shallower and quicker, so their paths stack in front of the defenders. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Double team: See Combo block.
Doubles: See 2x2.
Down: One play in a series. The offense gets four downs to gain 10 yards; the number on the graphic (1st, 2nd, 3rd, 4th) says how many of those tries it has used. Taught in Downs, Distance, and Field Position.
Down block: A block on a defender lined up inside you, hitting him from the side to push him toward the center and seal the inside of the hole. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Down by contact: The NFL’s rule for ending a run: the ball carrier is down when any part of his body other than his hands or feet touches the ground after he has been touched by an opponent. Contact can come first or second: a runner who slips untouched may get up and keep going, but if an opponent touches him while he is on the ground, he is down (in college he is down when his knee hits, touched or not). Taught in Officiating, Replay, and the Rules of the Ball.
Down judge: The official who straddles the line of scrimmage on one sideline (the side with the chain crew). He rules on offside, encroachment, false starts and illegal formations on his side, watches the receivers and the sideline nearest him, marks forward progress and runs the chain crew. Called the head linesman until 2017. Taught in Officiating, Replay, and the Rules of the Ball.
DPI: See Defensive pass interference.
Draft value chart: A table that assigns every draft pick a number of points so that teams can price trades. The original, built for the Dallas Cowboys around 1991, is called the Jimmy Johnson chart; newer charts are built from what picks actually produce. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Draw: See Draw play.
Draw play: A run disguised as a pass: the line sets up to pass block and lets the rushers run upfield, the quarterback shows a drop, and the ball is handed to the back late, after the linebackers have turned to cover. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Drive (concept): A concept in which one receiver runs a shallow cross at 2–4 yards and a teammate from the same side runs a dig at about 12 yards behind him, a high-low read of the linebacker in the middle. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Drive (possession): One team’s unbroken run of plays with the ball, from the moment it gets the ball until it scores, punts, turns it over, or the half ends. Taught in Downs, Distance, and Field Position.
Drive block: A one-on-one block straight ahead on the defender lined up on you, to move him back off the ball. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Drop (3/5/7-step): The quarterback’s steps backward from the snap to his throwing spot. From under center, 3-, 5- and 7-step drops end roughly 5, 7 and 9 yards deep; from the shotgun, which starts 5 yards back, the same depths take 1, 3 and 5 steps. Each drop is timed to a depth of route. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Dropback: A play on which the quarterback sets up to pass: every pass attempt, every sack and every scramble. In nflverse play-by-play it is the qb_dropback column, and the pass column equals 1 on the same plays. Taught in Working with nflverse Data in Python.
Dropper (DL in coverage): A defensive lineman, or an edge rusher who normally rushes, who drops into a short zone at the snap as part of a zone blitz or simulated pressure, usually into the window where the quarterback’s hot throw is meant to go. Taught in Zone Blitzes, Fire Zones, and Simulated Pressure.
Dummy call: A word or signal shouted at the line that means nothing, used to confuse defenders who are listening for the real calls. Defenses use them too. Taught in The Pre-Snap Phase.
Duo: A downhill gap-scheme run with no puller: two double teams drive the defensive tackles straight back, every other blocker takes the man on him, the double teams come off onto whichever linebacker fills, and the running back reads the Mike, hitting the gap he does not fill. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
DVOA: Defense-adjusted Value Over Average: a proprietary efficiency rating created by Aaron Schatz at Football Outsiders (now published by FTN) that scores every play against a league baseline for its situation and adjusts for the opponent; 0% is average. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Dynamic kickoff: The NFL’s kickoff format since 2024: the kicker’s ten teammates stand on the receiving team’s 40, five yards from the receiving team’s blockers, and nobody but the kicker and the returners may move until the ball hits the ground or a player in the landing zone or end zone. Taught in Kickoffs, Returns, and the Dynamic Kickoff.

E

E-T stunt: A two-man stunt in which the end goes first, crashing inside, and the defensive tackle loops around behind him to the outside, taking over the end’s rush lane. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Eagle front: A front name that means different things in different eras and staffs: Greasy Neale’s 1940s Philadelphia Eagles five-man line, Fritz Shurmur’s linebacker-heavy package with the 1980s Rams, and, in modern 3-4 playbooks, either an Okie whose ends pinch inside to 4i-techniques (what other staffs call a tite or mint front) or a one-side change-up in which an outside linebacker walks up onto the tackle and the end beside him reduces inside. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Early down: First or second down. The offense still has at least one more try before the down that decides whether it punts, so it can call almost anything, and the defense knows the least about what is coming. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
Edge pressure: A pressure built to win outside the offensive tackles: the extra rusher or rushers (an outside linebacker, nickel, cornerback or safety) come off the edge, often while the defensive end slants inside to drag the tackle with him. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Edge rusher: The modern catch-all name for the defender whose main job is pressuring the quarterback from outside the offensive tackle, whether he’s called a defensive end or an outside linebacker. Taught in The Twenty-Two.
Eight-man front: See Loaded box.
Eligible receiver: An offensive player allowed to catch a forward pass: one of the two players on the ends of the line, or any back (anyone lined up off the line, behind it), except a quarterback taking the snap under center. Taught in The Twenty-Two.
Eligible tackle: An offensive lineman, usually a tackle, who has reported eligible and lines up at the end of the line, so that he may catch a forward pass on that play. Taught in Formation Rules and the Language of Alignment.
Emergency third quarterback: Since 2023, a third quarterback on the 53-man roster who may dress for a game without counting against the game-day active limit, and enter only if both of the team’s other quarterbacks are injured or ejected. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
EMOL: See End man on the line of scrimmage.
EMOLOS: See End man on the line of scrimmage.
Empty: A formation with nobody in the backfield beside or behind the quarterback: all five eligible receivers line up out wide or on the line, most often three on one side and two on the other (3x2). Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Empty protection (five-man): Pass protection with no back or tight end blocking, just the five linemen, as when the offense lines up with an empty backfield; if a sixth defender rushes, the quarterback must get rid of the ball before he arrives. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Encroachment: A defensive foul: before the snap, a defender enters the neutral zone and touches an offensive player or the ball. The whistle blows at once; five yards. Taught in The Pre-Snap Phase.
End man on the line of scrimmage: The outermost defensive player lined up on the line of scrimmage on one side of the formation; the usual read key on option plays, because he is the defender an offense can most easily afford to leave unblocked. Taught in Option Football: Reading Defenders Instead of Blocking Them.
End zone: The 10-yard-deep area at each end of the field, between the goal line and the end line. Carry the ball into it, or catch or recover it there, and you score a touchdown. Taught in The Game in Fifteen Minutes.
End-around: A run in which a receiver who lined up outside comes back behind the line and takes a handoff from the quarterback, carrying the ball toward the other side of the field. One exchange; often paired with a fake run the opposite way. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
End-zone camera: A camera behind one end zone, looking straight down the field. It shows the blocking, the gaps between linemen and the running lanes better than any other angle; coaches film includes a high version of it. Taught in How to Watch a Broadcast Like You Mean It.
EP: See Expected points.
EPA: Expected points added: how much one play changed the offense’s expected points (EP after the play minus EP before it). Positive means the play helped the offense. Taught in Downs, Distance, and Field Position.
Erhardt-Perkins: A play-calling system named after Ron Erhardt and Ray Perkins, assistants on the 1970s New England Patriots, in which one word names a whole route combination that every receiver can run from any spot; associated with Bill Parcells’s Giants and Bill Belichick’s Patriots. Taught in Offensive Systems and Play-Calling Languages.
Even front: A defensive front whose down linemen are set in pairs, two on each side of the ball, with nobody head-up on the center: in practice a four-man line, the 4-3 family. Two tackles can cover only two of the three interior offensive linemen, so an even front always leaves the center or a guard uncovered. Most lean one tackle onto a shoulder of the center (a 1-technique) and set the other outside a guard (a 3-technique), which leaves one guard free; the direction of that lean is what Over and Under name. Taught in Even Fronts: 4-3 Over, Under, Wide-9, and the 46 Bear.
Exchange (man coverage on motion): A man-coverage answer to motion in which nobody follows the motion man across: the defenders slide over and swap receivers, so the defender on the side he arrives at picks him up. From the stands it looks like a zone bump; the difference is that each slid defender ends up squared up close on one receiver. Taught in Motion and Shifts as Weapons.
Expected pass rate: See xpass.
Expected points: What a situation (down, distance and yard line) is worth, on average, to the team with the ball: the average value of the next score in the half after thousands of past plays from the same situation, with the other team’s scores counted as negative. Taught in Downs, Distance, and Field Position.
Expected points added: See EPA.
Explosive play rate: The share of a team’s plays that gain a big chunk. Coaching staffs often count runs of 12+ yards and passes of 16+; analysts often use 10+ and 20+ (definitions vary by source). Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Extra point: The one-point kick after a touchdown. In the NFL it has been snapped from the 15-yard line since 2015, which makes it a 33-yard kick. Taught in The Game in Fifteen Minutes.
Eye candy: Motion and fakes by players who will not get the ball, designed to pull defenders’ eyes and first steps the wrong way so the real play gains a fraction of a second or a gap. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Eye discipline: Looking at the right thing at the right moment: a zone defender’s eyes on the quarterback and his key receivers, a man defender’s on his man. Many big plays against sound coverage start with a defender’s eyes in the wrong place. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.

F

Fade: A route in which the receiver releases outside and runs toward the back corner of the end zone, with the ball thrown over his outside shoulder where only he can reach it; the classic red-zone throw against press-man coverage. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Fair catch: A catch of a punt or kickoff by a returner who waves one fully extended arm above his helmet while the ball is in the air. He may not be hit, the ball is dead where he catches it, and he may not run with it. Taught in Field Goals, Extra Points, and the Punting Game.
Fair-catch kick: A free field-goal try, place-kicked from the spot of a fair catch with the defense ten yards away and no snap. The receiving team may choose it after any fair catch, even with time expired; a successful kick is worth three points. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Fake punt / fake field goal: A play in which the kicking team lines up to punt or kick but runs or passes instead, usually with the punter, holder or personal protector handling the ball, to keep possession on fourth down or score. Taught in Field Goals, Extra Points, and the Punting Game.
False start: An offensive foul: after the ball is ready for play, a set offensive player moves in a way that imitates the start of the play (for example a lineman lifting his hand off the ground). The whistle blows at once; five yards. Taught in The Pre-Snap Phase.
Field goal: Three points for kicking the ball, held on the ground by a holder, through the goal posts on a play from scrimmage. It can be tried from anywhere, on any down; a miss gives the other team the ball at the spot of the kick (or at its own 20, if the kick was from inside it). Taught in The Game in Fifteen Minutes.
Field goal range: The yard line beyond which a coach believes his kicker, in today’s conditions, makes a field goal often enough that kicking beats going for it or punting. Add 18 to the line of scrimmage for the kick’s length; in the NFL range usually begins somewhere around the opponent’s 35 to 40. Taught in Field Goals, Extra Points, and the Punting Game.
Field judge: The deep official on the line judge’s side, about 20 yards past the line near the sideline, with the same job as the side judge on that half of the field. On field goals he stands under one upright. Taught in Officiating, Replay, and the Rules of the Ball.
Field position: Where the ball is on the field, treated as an asset: the closer a team starts to the opponent’s end zone, the more its possession is worth. Taught in Downs, Distance, and Field Position.
Field side: When the ball is on a hash, the side of the field with more room between the ball and the sideline. Taught in The Game in Fifteen Minutes.
Fifth-year option: A team’s right, written into every first-round rookie contract, to add a fifth season at a set price. It must be exercised after the player’s third season; since the 2020 agreement the option year is fully guaranteed once exercised, and its price depends on his playing time and Pro Bowls. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Fill: A linebacker attacking downhill into the gap a run is aimed at, to meet the lead blocker or the ball carrier as close to the line of scrimmage as he can. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Film-study protocol: A fixed routine for studying each snap on game film: freeze the picture at the snap and check your pre-snap read, then watch the play once for each group (the offensive line, the quarterback, the coverage, the receivers and backs), and finish with one line saying why the play worked or failed. The order runs from what sets the play’s clock to what uses it. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
Fire zone: The most common zone blitz: five rushers, with three defenders deep (each guarding a third of the field) and three underneath (a seam-flat defender on each side and one in the middle), usually with a defensive lineman as one of the three underneath. Taught in Zone Blitzes, Fire Zones, and Simulated Pressure.
First down: The first play of a new series of four downs, earned by reaching the line to gain. Also the act of earning one (‘they picked up the first down’). Taught in Downs, Distance, and Field Position.
First touching: A kicking-team player touching a punt beyond the line of scrimmage before any receiving player has touched it. It is a violation, not a foul: the ball stays live, and the receiving team may take the ball at the spot of first touching or at the end of the play, whichever it prefers. Taught in Field Goals, Extra Points, and the Punting Game.
Five-man pressure: A pass rush with exactly five rushers: the usual four plus one linebacker or defensive back, leaving six defenders in coverage. The most common kind of blitz by far. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Flanker: See Z receiver.
Flare: A running back’s quick release toward the sideline on a shallow arc that bends slightly upfield, used as a quarterback’s outlet or to pull a linebacker wide. Many playbooks treat flare and swing as the same route. Taught in Play-Action, Bootlegs, and Screens.
Flat route: A route to the flat, the area near the sideline within a few yards of the line of scrimmage. The shallowest outside route (the 1 in many route trees). Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Flat zone: The short area near the sideline, from the line of scrimmage to about 6 or 7 yards deep and from roughly the slot or the numbers out to the sideline: where flat routes, quick outs and swing passes are caught. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Flex defense: Tom Landry’s Dallas Cowboys version of the 4-3, from the mid-1960s: two of the four defensive linemen line up a yard or so off the ball, read the blocks, then fill an assigned gap, so that every gap has an owner. Built to stop ‘run to daylight’ running games like Vince Lombardi’s. Taught in From the Single Wing to the 1970s Scoring Drought (1906–1977).
Flexbone: An option formation that grew out of the wishbone: one fullback behind the quarterback, two slotbacks just off the line behind and outside the tackles, and two wide receivers on the line, usually with no tight end. Long the offense of Navy, Air Force and Army, and of Georgia Tech under Paul Johnson. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Floater: Under the dynamic kickoff, a receiving-team player in the setup zone who lines up behind the restraining line instead of on it: up to two in 2024, three in 2025 and four from 2026. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Flood: A three-receiver concept that puts three receivers at three depths near one sideline (a deep route, an intermediate out or sail route, and a flat route), so two defenders face three receivers. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Flow (fast / slow): The direction and speed of the backfield’s action at the snap, as a linebacker reads it. Fast flow (the ball going sideways quickly, as on outside zone or a toss) tells him to run with it and stay inside-out; slow flow (the ball coming straight downhill, or slowly, as on inside zone, iso, draws and counters) tells him to press his gap and not overrun it. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Fly motion: The Wing-T’s name for jet-style motion: a wingback or slot sprinting across the formation behind an under-center quarterback, usually for the fly sweep. Many teams use ‘fly’ and ‘jet’ for the same thing. Taught in Motion and Shifts as Weapons.
Fly route: See Go route.
Force (defender): The defender responsible for the outside edge of a run toward his side: he keeps the ball carrier from getting outside him and turns (forces) the ball back inside toward his teammates. Depending on the call he may be an end, an outside linebacker, a safety or a cornerback. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Formation strength: The side of a formation treated as its ‘strong’ side, decided by a rule: usually the tight end’s side, sometimes the side with more receivers or the wide side of the field. Offenses name formations by it and defenses set their front and coverage to it. Taught in Formation Rules and the Language of Alignment.
Forward progress: The farthest point toward the opponent’s goal that the ball reached before the ball carrier was stopped. The ball is spotted there, not where he ended up after being driven back, and officials blow the play dead once his progress is stopped. Taught in Officiating, Replay, and the Rules of the Ball.
Four verticals: A concept in which four receivers run straight up the field at once, two outside and two up the seams, so the defense’s two or three deep defenders face four deep routes. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Four-down territory: The part of the opponent’s half, roughly from its 40 to the edge of the red zone (coaches draw it differently), where a punt buys little field and a field goal is long or uncertain, so the offense plans to use fourth down if it needs to. On short yardage, most NFL offenses now treat everything past midfield this way. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
Four-man rush: The standard pass rush: four defenders rush the quarterback and the other seven cover. Who the four are can vary; the count is what matters. Taught in A First Look at Defense.
Four-minute offense: The mirror image of the two-minute drill: a team protecting a lead late in the game runs the ball, keeps receivers in bounds and lets the play clock run down before every snap, so that each first down takes a minute or more off the clock. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Fourth-down bot: See Fourth-down model.
Fourth-down model: A model that estimates a team’s win probability if it goes for it, kicks a field goal or punts on fourth down, by combining conversion, field-goal and punt probabilities with a win-probability model, and recommends the option worth the most. Published live, play by play, it is called a fourth-down bot. Taught in Win Probability and Decision Analysis: Fourth Downs, Two-Pointers, Timeouts.
Frame (tracking): One snapshot in a tracking file: every player’s position at one instant. NFL tracking has 10 frames a second, so frame 31 comes 3 seconds after frame 1. Taught in Tracking Data and the Big Data Bowl.
Franchise tag: A one-year contract a team may impose on one of its expiring players each year, priced at roughly the average of the five largest cap numbers at his position (or 120% of his previous salary, if higher). The non-exclusive tag lets other teams bid at the price of two first-round picks; the exclusive tag forbids talking to other teams at all. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Free agency (1993): The system, in force in the NFL since March 1, 1993, that lets a veteran whose contract has expired sign with any team (today, after four accrued seasons). An accrued season is one in which the player was on full pay status for at least six regular-season games; a player with three is a restricted free agent, whose old team can keep him by matching an offer, and one with fewer than three is an exclusive-rights free agent, who can negotiate only with his old team if it tenders him. The system came out of the January 1993 settlement of the players’ antitrust lawsuits. Taught in 1978 and the Passing Revolution (1978–1999).
Free kick: A kick that puts the ball in play without a snap, from a tee or the ground, with both teams held behind restraining lines until it is kicked: kickoffs, the kick after a safety, and the rare fair-catch kick (a field-goal try a team may take from the spot of a fair catch). Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Free play: A snap on which the defense has already committed a foul that lets play go on (usually offside), so the offense can take a risk knowing it may either keep the result or take the penalty instead. Taught in Contact Rules and Penalties as Strategy.
Free rusher: A pass rusher nobody is assigned to block, either because the defense sent more rushers than the protection had blockers or because the blockers made a mistake. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Free safety: The safety who usually plays deeper and more in the middle of the field, ‘free’ to go wherever the ball goes rather than covering a particular receiver. Taught in The Twenty-Two.
Fringe: See Four-down territory.
Front seven: The defensive linemen and linebackers together, the defenders who line up near the ball and play the run first. (In a nickel defense it is often six, plus whoever fills the seventh spot.) Taught in The Twenty-Two.
FTN charting data: Per-play charting by FTN Data’s human charters, from 2022 on and updated weekly during the season: where the quarterback lined up, motion, play-action, RPOs, screens, blitzers, drops and more. It does not include the coverage. Taught in Working with nflverse Data in Python.
Full house backfield: Any backfield with three running backs behind a quarterback who is under center (four players in the backfield in all), as in the T-formation, the wishbone and the Power I. Today it is mostly a goal-line and short-yardage look. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Fullback: A bigger, blocking-first back who lines up in front of or beside the running back and leads him into the hole; now a rare, specialist position in the NFL. Taught in The Twenty-Two.
Fumble: A ball carrier losing control of the ball before he is down. Either team can recover it; if the defense does, it is a turnover. Taught in Downs, Distance, and Field Position.
Fumble through the end zone (touchback): A fumble that goes forward into the opponent’s end zone and out of bounds there (out the side or the back). The offense loses the ball even though nobody recovered it: it is a touchback, and the defense takes over at its own 20. Taught in Officiating, Replay, and the Rules of the Ball.

G

G front: A front tag that moves the nose off the center onto a guard’s inside shoulder (a 2i-technique, ‘G’ for guard), changing the blocking angles for the center and the guard on inside runs. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Game charting: Recording every snap of a game as one row of the same fixed fields (situation, personnel, formation, motion, the defense’s look, what happened after the snap, the result), coded the same way every time, so that a game becomes data you can count, compare and check your predictions against. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
Game clock: The scoreboard clock that counts down each 15-minute quarter. It runs during plays and, depending on how the last play ended, between them. Taught in The Game in Fifteen Minutes.
Game plan: The slice of a team’s playbook chosen for one opponent, plus the rules for using it: which plays, formations, coverages and pressures to use in which situations, and which of the opponent’s players to attack or avoid. Built early in the week, taught in practice, and printed on the call sheet for Sunday. Taught in The Game Plan: A Week Inside an NFL Building.
Game script: How the score shapes a team’s play calling, and so its players’ usage: a team that leads late runs to burn clock (more carries for its running backs), and a team that trails throws to catch up (more targets for its receivers and its pass-catching back). Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Game-management staff: See Analytics staff.
Game-plan defense: A defense rebuilt for each opponent rather than run the same way every week: the staff decides what that offense most needs (a player, a concept, a part of the field), designs alignments and coverages to take it away, and chooses in advance what it will concede instead. Most associated with Bill Belichick’s Giants and Patriots defenses. Taught in Case Study: Belichick and Game-Plan Football.
Game-plan package: A small group of plays, formations or calls built for one opponent and one purpose (say, three answers to that defense’s favorite third-down blitz), taught that week, and often retired after the game. Taught in The Game Plan: A Week Inside an NFL Building.
Gap (A, B, C, D): A space between two adjacent players on the offensive line, named by letter outward from the center: A between center and guard, B between guard and tackle, C outside the tackle, D outside a tight end. Defenses assign each defender a gap to fill. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Gap exchange: A planned swap of gap responsibilities between two defenders after the snap, such as an end crashing inside while the linebacker behind him takes the outside gap; the scrape exchange against the zone read is the best-known version. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Gap integrity: The principle that every gap the offense can run through has exactly one defender responsible for it, and that each defender stays in his gap until the ball shows where it is going, so no gap is left empty and none has two defenders. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Gap scheme: A family of running plays in which each blocker is assigned a man or a gap before the snap, chosen to give him a good angle (usually a down block), and extra blockers (pullers, a fullback, a tight end) are brought to a hole chosen in advance. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Garbage-time filter: Dropping plays where the score or the clock dictates the call rather than the game plan. This course’s version keeps plays with the offense’s win probability between 10% and 90% that are not in the last two minutes of either half. Analysts choose their own cut-offs, so always state yours. Taught in Working with nflverse Data in Python.
Get-off: A pass rusher’s first movement at the snap: how quickly he reacts to the ball moving and gets across the line of scrimmage. Tracking data measures it in tenths of a second, and a tenth of a second is most of a yard. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Ghost (rush move): A speed move with no hand contact at all, timed to the blocker’s punch: at the instant the tackle strikes, the rusher turns his inside shoulder away (and dips it), so the punch hits air and the tackle lunges forward, then bends around him. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Give / keep: The quarterback’s two choices on a read play: give the ball to the running back at the mesh, or keep it and run himself. Coaches call the read ‘give’ or ‘pull’ depending on which answer is the default. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Glance RPO: A post-snap RPO in which an outside receiver runs a glance (a quick, skinny post angled inside) behind a linebacker or safety who is responsible for the run; if that defender steps up to stop the run, the quarterback pulls the ball and throws the glance behind him. Taught in Run-Pass Options: Plays That Are Two Plays.
Glide motion: A wide receiver motioning from a wide spot in toward the ball, with the snap coming when he is about halfway there, so he starts the play already moving inside: good for crossing routes and crack blocks. Taught in Motion and Shifts as Weapons.
Go route: A straight sprint upfield to run past the defender (the 9 in many route trees). Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Go-for-it decision: The choice on fourth down between going for the first down (or touchdown), kicking a field goal and punting, increasingly made with expected-points or win-probability models rather than habit. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Goal line: The line that separates the field of play from the end zone. It belongs to the end zone: a ball on, above or past it, held by a runner, is a touchdown. Taught in The Game in Fifteen Minutes.
Goal-line defense: A defensive package for the last yard or two, in which extra linemen and linebackers replace defensive backs (classically a 6-2 or 5-3 front) so that every gap along the line is filled by a defender lined up low and close to the ball. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Goal-line formation: The offense’s heaviest formation, used inside the 2- or 3-yard line and on short yardage: quarterback under center, two backs, three tight ends (or extra linemen) and no wide receivers, everyone aligned tight to the ball with narrow splits (23 personnel, or 14, or a jumbo grouping). Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Green dot: The green sticker on the back of a helmet that has the radio speaker, and by extension the player wearing it. Only one such player per team may be on the field at a time. Taught in What a Play Really Is.
GT counter: See Counter.
Guaranteed money: Contract money a team must pay even if it releases the player. ‘Fully guaranteed at signing’ money is owed no matter what; other money is guaranteed only for injury, or becomes guaranteed on a later date if the player is still on the roster. Reported ‘total guarantees’ usually add the kinds together. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Guard: One of the two offensive linemen on either side of the center. Taught in The Twenty-Two.
Gunner: On a punt, one of the two players split out wide who sprint downfield to tackle the returner; the other side assigns one or two blockers (vices) to slow each of them. Taught in The Twenty-Two.

H

H / F (move player): Letters for ‘move’ players whose job changes with the grouping: a slot receiver, a second tight end, an H-back or a fullback. Which letter means what varies from team to team. Taught in Formation Rules and the Language of Alignment.
Hail Mary: A long, high pass thrown into a crowd of receivers and defenders near or in the end zone on the last play of a half, hoping someone on the offense catches it or a tipped ball falls to a teammate. Named after Roger Staubach’s 1975 playoff touchdown. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Half the distance: The cap on penalty yardage near a goal line: when the full penalty would move the ball more than halfway to the offending team’s goal line, the ball moves only halfway instead. Taught in Contact Rules and Penalties as Strategy.
Half-slide: The NFL’s most common six-man protection: the center and the two linemen on one side slide that way and block gaps, the two linemen on the other side block the man in front of them, and the running back takes the first extra rusher on the man side. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Halfback: See Running back.
Halftime adjustment: A change to the game plan made during the 13-minute halftime break: re-ranking the calls on the sheet, changing a protection, a coverage mix or who covers whom, or leaning on a play that worked. Almost always a choice from plays already practiced that week, not a new play. Taught in In-Game Adjustments, Tempo, and the Sideline Battle.
Hands team: The receiving team’s special lineup for an onside kick: its surest-handed players (receivers, tight ends, running backs, defensive backs) placed to catch or fall on a short, bouncing ball. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Hard corner: A Cover 2 cornerback. He lines up about 5 to 7 yards off the outside receiver (or presses him) with outside leverage, jams or redirects the receiver at the snap, and then stays short to guard the flat instead of bailing to a deep zone. He is also the defense’s force player against runs to his side. Taught in Cover 2 and Tampa 2.
Hard count: A cadence with a sudden change in volume or rhythm, meant to make defenders think the ball is about to be snapped and jump offside. Often there is no intention of snapping the ball at all. Taught in The Pre-Snap Phase.
Hash marks: The two rows of short lines running the length of the field, 70 feet 9 inches in from each sideline in the NFL. Every play starts on or between them; if the last play ended outside them, the ball goes on the nearer one. Taught in The Game in Fifteen Minutes.
Hat math (numbers advantage): Counting blockers against defenders (‘hats’) in the box or at the point of attack. ‘A hat on a hat’ means every defender has a blocker; a defense with one more defender than the offense has blockers has a free tackler. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Hawk-Eye measurement: See Virtual measurement.
Head coach: The person in charge of the whole team and staff. On game day he makes the big decisions (fourth downs, challenges, timeouts) and sometimes calls the offense’s or defense’s plays as well. Taught in What a Play Really Is.
Head-up: Lined up directly across from an offensive player, nose to nose, rather than on one of his shoulders. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Heavy hand: A three-point stance with a lot of the lineman’s weight leaning on his down hand (shoulders forward, knuckles pressing white). It usually means he is about to fire forward to run-block; a light hand, with the weight back on the heels, suggests he is about to step back into a pass set. Taught in How to Watch a Broadcast Like You Mean It.
Heavy personnel: Any grouping with fewer than three wide receivers, so more tight ends, backs or linemen on the field. 12, 21, 13 and 22 are the common ones; some people keep the word for the very biggest groupings (13, 22, jumbo). Taught in Personnel: Who’s on the Field Before Anything Else.
Heavy stance: See Heavy hand.
Helmet radio: The one-way speaker in one offensive player’s and one defensive player’s helmet that lets a coach talk to him between plays. It cuts off with 15 seconds left on the play clock or at the snap. Taught in What a Play Really Is.
High-low read: Putting two receivers in one defender’s area at two depths, one above him and one below, and throwing to whichever one he leaves. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Hip-drop tackle: A tackle in which the tackler wraps the runner from behind or the side, swings his hips and legs off the ground, and drops his weight onto the runner’s legs at or below the knee. Banned by the NFL in 2024; fifteen yards and an automatic first down. Taught in Contact Rules and Penalties as Strategy.
Hitch: A route that pushes upfield, stops, and turns back to face the quarterback. Short versions (5–6 yards) are usually called hitches; deeper ones (10–14 yards), which turn back toward the middle, are curls, the 4 in many route trees. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Hitch-seam: A two-receiver quick concept: the outside receiver runs a hitch and the inside receiver a seam straight up the field, a high-low read on the defender between them. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Holder: The player, usually the punter, who catches the long snap on a field goal or extra point and sets the ball on the ground for the kicker. Taught in The Twenty-Two.
Hole numbering: An offense’s numbers for the places a run can hit, counted outward from the center, usually even numbers to one side and odd to the other; a two-digit run call names the ball carrier and the hole (‘24’: the 2-back through the 4 hole). Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Hole shot: A pass thrown into the gap along the sideline behind a Cover 2 cornerback, who is guarding the flat, and in front of the deep-half safety, who has to come from near the hash: usually a fade or go route caught 18 to 25 yards downfield, on time, before the safety gets there. Taught in Cover 2 and Tampa 2.
Hole zone: The middle of the field in front of the deep middle defender, roughly 8 to 15 yards deep between the hash marks, where digs and crossing routes arrive. Some staffs reserve ‘rat’ for a lower spot in the same lane, 5 to 8 yards deep. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Hook / curl defender: A zone defender, usually a linebacker, who drops to the area between the offensive tackle and the numbers about 8 to 12 yards deep (the hook and curl zones), takes away in-breaking routes, carries a slot receiver who runs straight up the seam, and sinks under curls while he reads the quarterback. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Hook zone: The short-to-intermediate area inside the curl zone, around the hash marks and over the offensive tackles, about 5 to 12 yards deep; the linebackers’ home in most zone coverages. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Horizontal passing game: An offense built on short, timed throws toward the sidelines and across the field, caught a few yards past the line of scrimmage and turned into gains by the run after the catch. It uses the pass to do the running game’s job (gain four or five yards, keep the ball, stretch the defense from side to side), which is why its throws are often called extended handoffs. Bill Walsh’s 49ers made it the core of the West Coast offense. Taught in Case Study: Bill Walsh’s 49ers and the West Coast Offense.
Horizontal stretch: Putting receivers on both sides of an underneath defender (or spread across the field) at about the same depth, so a zone defender can’t cover both and the quarterback throws to the one he leaves. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Horse-collar tackle: Grabbing the inside back or side collar of a ball carrier’s shoulder pads or jersey and pulling him down. Banned in the NFL since 2005; fifteen yards. Taught in Contact Rules and Penalties as Strategy.
Hot route: A throw built into the play to beat an extra rusher: when the defense sends more rushers than the protection can block, the quarterback throws at once to a receiver running into the area the rusher just left. (In Madden the term means a pre-snap route change, which is something else.) Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Huddle: The brief circle, usually seven to ten yards behind the ball, in which the quarterback (or the green-dot defender) repeats the play call to his teammates before they line up. Taught in What a Play Really Is.
Hurry-up offense: An offense snapping the ball as fast as it can, usually without a huddle, to run more plays, tire the defense and keep it from substituting or disguising. Every team uses it when it is short of time (the two-minute drill); a few use it as a weapon all game. Taught in In-Game Adjustments, Tempo, and the Sideline Battle.
Hybrid defense: See Multiple defense.
Hybrid edge: The defender at the end of the line who is part defensive end and part outside linebacker: big enough to set the edge against a tackle, fast enough to rush the passer from a two-point stance, and agile enough to drop into a short zone. A 4-3 team lists him as a defensive end and a 3-4 team as an outside linebacker; since the 2000s many teams and draft boards simply call him an EDGE. DeMarcus Ware, James Harrison and Von Miller are classic examples. Taught in Dynasties and Counterpunches (2000-2016).

I

I-formation: A two-back formation with the quarterback under center, the fullback directly behind him (about 4-5 yards deep) and the tailback directly behind the fullback (about 7 yards deep), so the three form an ‘I’. Usually 21 personnel. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Illegal contact: A defender initiating contact that impedes a receiver more than five yards past the line of scrimmage before the pass is thrown, while the quarterback is still in the pocket with the ball. Five yards and an automatic first down. Taught in Contact Rules and Penalties as Strategy.
Illegal formation: A five-yard foul on the offense for lining up wrongly at the snap: fewer than seven players on the line, a player who is neither on the line nor a yard behind it, and similar alignment faults. Taught in Formation Rules and the Language of Alignment.
Illegal hands to the face: Pushing, punching or grabbing an opponent’s face mask, helmet or neck area with the hands, by a blocker or a defender (the stat sheet calls it illegal use of hands). Ten yards against the offense; five yards and an automatic first down against the defense. Taught in Contact Rules and Penalties as Strategy.
Illegal man downfield: The foul when an ineligible offensive player (usually a lineman) is too far past the line of scrimmage when a forward pass is thrown: in the NFL, entire body more than one yard beyond the line unless he got there while blocking a defender he engaged at the line; in college, more than three yards beyond the neutral zone. Five yards in both. Taught in Run-Pass Options: Plays That Are Two Plays.
Illegal motion: An offensive foul: at the snap, a player is moving toward the line, more than one player is moving, or a player who lined up on the line is still moving. Five yards; the play goes on and the defense may accept or decline it. (Failing to reset for a full second after a shift is the closely related illegal shift.) Taught in The Pre-Snap Phase.
Illusion of complexity: The goal of making a few plays look like many, by dressing the same play in different formations, personnel groups and motions, and many plays look like one, by running different plays from the same look, so the defense must prepare for far more than the offense has to learn. Taught in Constraint Theory: How Plays Talk to Each Other.
Implied team total: The points a team is expected to score according to the betting lines: half the game total plus half the point spread for the favorite, or minus half the spread for the underdog. Fantasy players use it to forecast touchdowns and game script. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
In route: See Dig.
In-line tight end: A tight end lined up on the line of scrimmage right next to a tackle (attached), where he can block like a lineman or release into a route. Taught in Formation Rules and the Language of Alignment.
Ineligible downfield: See Illegal man downfield.
Ineligible receiver: An offensive player who may not catch a forward pass: the interior linemen, anyone wearing 50-79 who hasn’t reported as eligible, any player covered up inside the end of the line, and a quarterback taking the snap under center. Taught in The Twenty-Two.
Injured reserve: The list for injured players who are removed from the 53-man roster, freeing their spots. A player placed on it during the season must sit out at least four games; a team may bring back a limited number (eight a season) and the rest are out for the year. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Insert (zone insert): A zone tag in which a fullback, H-back or tight end leads up through a gap to block a linebacker, adding a blocker at the point of attack. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Inside help: A defender positioned toward the middle of the field from a man defender (the deep middle safety, or a robber underneath) who can take routes that break inside, so the man defender can play outside leverage and take away the sideline. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Inside zone: A zone run aimed at the play-side guard or B gap, in which double teams drive the defensive linemen back and the running back reads for a crease, often cutting back. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Install: Teaching a set of plays to the players through meetings, walk-throughs and practice. Also the set of plays taught in one session (‘the third-down install’). Taught in What a Play Really Is.
Intentional grounding: A foul by a passer who, facing an imminent loss of yardage, throws a pass that isn’t in the direction and vicinity of an eligible receiver. It costs a loss of down and 10 yards (or the spot of the pass, if that is worse), and a safety if he throws it from his own end zone. A passer who is or has been outside the tackle box may throw it away freely if the ball reaches the line of scrimmage. Taught in Officiating, Replay, and the Rules of the Ball.
Intentional safety: Deliberately giving the opponent two points by having the ball carrier (usually the punter) run out of the back of his own end zone, to burn clock and to replace a dangerous punt from deep in your own territory with a free kick from your own 20. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Interception: A forward pass caught by a defender. His team takes possession wherever his return ends. Taught in Downs, Distance, and Field Position.
Inverted veer: An option run in which the line blocks power with a pulling guard, the running back sweeps wide, and the quarterback reads the play-side end: if the end widens with the back, the quarterback keeps inside behind the puller; if he squeezes, the quarterback gives outside. The roles of the veer are inverted: the quarterback is the inside runner. Also called the dash read. Taught in Option Football: Reading Defenders Instead of Blocking Them.
IR: See Injured reserve.
Iso: A run in which the linemen block the defensive linemen in front of them and the fullback leads through the hole onto a linebacker, ‘isolating’ that linebacker one-on-one against the fullback while the back reads the block. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Isolation: See Iso.

J

Jailbreak screen: A screen in which some or all of the offensive linemen skip pass protection and sprint out to block in space at the snap, leaving the rushers free, while a receiver steps back to catch a quick throw behind them. Names vary by playbook; some teams call the tunnel screen a jailbreak. Taught in Play-Action, Bootlegs, and Screens.
Jammer: See Vice.
Jet motion: A receiver (or back) sprinting across the formation, parallel to the line, timed so that the ball is snapped just before he reaches the quarterback. He is at full speed at the snap, ready to take a jet sweep or to fake one. Taught in Motion and Shifts as Weapons.
Jet sweep: A run in which a receiver (or back) in jet motion takes a handoff, or a tiny forward flip, from the quarterback at full speed as he crosses the formation, and races for the edge on the side he is running toward. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Joker: See Move tight end.
Jumbo (six offensive linemen): A grouping with a sixth offensive lineman on the field, usually standing where a tight end would. He is ineligible to catch a pass unless he reports to the referee as eligible before the play. Taught in Personnel: Who’s on the Field Before Anything Else.
Jump set: An aggressive pass set in which a lineman moves forward or flat to meet the rusher at or near the line, taking away his running start; used most with quick throws. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.

K

Keeper: A quarterback run off a run fake: he shows the handoff, keeps the ball and runs, usually around the end the fake drew inside. On a bootleg it is the quarterback’s choice to run when nobody has stayed outside to stop him; some playbooks also call the whole bootleg a ‘keep’. Taught in Play-Action, Bootlegs, and Screens.
Key (read key, defense): The offensive player (or two) a defender watches at the snap to learn whether the play is a run or a pass and where it is going. For an off-ball linebacker it is usually the guard nearest him (often both guards) and the near running back. Not to be confused with an option play’s read key, the defender the quarterback reads. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Kick coverage unit: The kicking team’s eleven on a kickoff (or a punt): the players who run down the field to tackle the returner. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Kick slide: An offensive tackle’s pass-set footwork: the outside foot kicks back and out, the inside foot slides after it, feet never crossing, so he moves backward and sideways while staying square to the rusher. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Kick-catch interference: A kicking-team player getting in the way of, or touching, a receiver who is trying to catch a punt or kickoff in the air, whether or not he signaled for a fair catch. The penalty is 15 yards from the spot of the foul. Taught in Field Goals, Extra Points, and the Punting Game.
Kick-out: A block on the end man of the defense from the inside, pushing him toward the sideline so the run can hit inside him; usually thrown by a pulling guard, a fullback or an H-back. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Kicker: The specialist who kicks field goals, extra points and kickoffs. Taught in The Twenty-Two.
Kickoff: The free kick that starts each half and follows every touchdown and field goal: one team kicks the ball off a tee from its own 35 to the other team. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Kill call: A system in which two plays are called in the huddle. At the line the quarterback either runs the first or ‘kills’ it (‘Kill, kill!’) to run the second, often choosing by how many defenders are near the line. Taught in The Pre-Snap Phase.
Kneel-down: See Victory formation.

L

Landing zone: Under the dynamic kickoff, the area between the receiving team’s goal line and its 20-yard line where the kick must land. A kick that lands there is live: the receiving team has to field it, and the kicking team may recover it. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Landmark: A spot on the field (a depth plus a width keyed to the hash marks, the numbers or a receiver) that a zone defender aims for on his drop, so that the zones are spaced the same way on every play. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Late rotation: A rotation timed to start at the snap or just after it, not during the cadence, so the quarterback gets no clean look at the real coverage before the play begins. Taught in Disguise, Rotation, and Split-Field Coverage.
Lateral: See Backward pass.
Launch point: The spot where the quarterback sets his feet to throw at the end of his drop; linemen set their depth to it so rushers are kept away from that exact spot. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Lead block: A block by a back (usually a fullback) who runs through the hole ahead of the ball carrier and blocks the first defender to show, often a linebacker. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Leak: A late release by a tight end or back who first sells a block or a run fake, then slips into the space the defense has abandoned, often running against the flow of the play (for example, the tight end on the run-fake side releasing into the flat the quarterback just rolled away from, for a throwback). Taught in Play-Action, Bootlegs, and Screens.
Levels: A concept in which two receivers on the same side run in-breaking routes at two depths (a short in at about 5 yards and a dig at about 12), a high-low read of the linebacker between them. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Leverage (game situation): How much the next play can move win probability in a given situation, measured against an average play. A one-score game in the last minutes is high leverage; a blowout is close to zero. Taught in Win Probability and Decision Analysis: Fourth Downs, Two-Pointers, Timeouts.
Leverage (inside / outside): Which side of a receiver a defender lines up on. Inside leverage protects the middle of the field and concedes routes toward the sideline; outside leverage protects the sideline and concedes routes inside. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Leverage tackling: Tackling from a position that keeps the ball carrier on one side of you (usually inside-out, so that his only escape is toward the sideline and your help), striking with the near shoulder at the near thigh and wrapping, rather than launching head-on for a big hit. The Seattle Seahawks taught it as ‘hawk tackling’, borrowed from rugby. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Light box: A box with no more defenders than the offense has blockers, so every run defender can be blocked and nobody is left over to make the tackle. Against a one-back offense with six blockers, six or fewer. It usually means the defense has spent players on pass coverage, and it invites the run. Taught in A First Look at Defense.
Light-box run game: An offense built to run the ball into the light boxes two-high defenses leave (six or fewer defenders against a one-back offense), with as many blockers as the defense has run defenders, or one more (a second tight end, a fullback or a running quarterback). A steady four- or five-yard run against a light box is the price a two-high defense has agreed to pay; the light-box run game collects it and makes the defense bring a safety down. Taught in The Modern Era: McVay, Mahomes, Two-High, and the Under-Center Comeback (2017-2025).
Line judge: The official who straddles the line of scrimmage on the sideline opposite the down judge, with the same duties on his side: offside, false starts, illegal formation, the near receivers and sideline, forward progress, and whether a pass was thrown from beyond the line. Taught in Officiating, Replay, and the Rules of the Ball.
Line of scrimmage: The imaginary line across the field through the ball before a play. Each team must stay on its own side of it until the snap. Taught in Downs, Distance, and Field Position.
Line to gain: The yard line the offense must reach to earn a new first down, normally 10 yards beyond where the series began. On TV it is the painted yellow line. Taught in Downs, Distance, and Field Position.
Linebacker: A defender who lines up behind the defensive line (the second level) and does a bit of everything: tackling runners, covering short passes and sometimes rushing the passer. Taught in The Twenty-Two.
Loaded box: A box with two or more defenders more than the offense can block; against a one-back offense with six blockers, eight or more (“eight in the box”). Usually built by bringing a safety down, to stop the run at the cost of pass coverage. Taught in A First Look at Defense.
Log block: A block by a puller who meets an end man who has crashed inside: instead of kicking him out, the puller gets his head and body outside the defender and seals him in, and the ball carrier bounces outside the block. Some coaches call it a wrap, though others use ‘wrap’ for any puller who swings around a block and turns up. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Long arm: A power rush move: the rusher locks one arm straight into the blocker’s chest, so the blocker cannot reach him, and drives him back, keeping the other hand free to shed the block and escape. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Long snapper: The specialist who snaps the ball the long distance back to the punter or holder on kicking plays. Taught in The Twenty-Two.
Look-off: The quarterback deliberately looking at one receiver or area, often with his shoulders turned that way too, to draw a defender who reads his eyes (usually a safety or a robber) toward it, then throwing somewhere else, into the space that defender left. Taught in What Beats What: Reading Coverage and Pass Concepts Versus Coverages.
Lurk: A free defender in man coverage, often one who lines up as a blitzer or a deep safety, who drops at the snap into the shallow middle (roughly 5 to 10 yards deep) to sit under crossing routes and hot throws. A disguised cousin of the robber. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.

M

Man coverage: Pass coverage in which each defender is assigned one eligible receiver and follows him wherever he goes. Taught in A First Look at Defense.
Man everywhere he goes: See MEG.
Man only deep: See MOD.
Man protection: A pass protection in which each blocker is assigned a specific defender before the snap: usually the five linemen take the four defensive linemen and one linebacker, and the running back takes the next linebacker. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Man-beater: A pass concept designed to beat man coverage, usually by crossing routes, rubs, or routes that break away from a defender’s leverage, rather than by stretching a zone defender. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Man-free: See Cover 1.
Man/power blocking: See Gap scheme.
Man/zone indicator: Reading the defense’s reaction to motion as a clue to its coverage: a defender who follows the motion man across suggests man coverage; defenders who shuffle over without following suggest zone. A strong hint, not a guarantee. Taught in Motion and Shifts as Weapons.
Master pre-snap checklist: The course’s complete pre-snap routine, run in the same order before every snap in roughly twenty seconds: situation, personnel, formation and strength, motion response, box, shell, leverage, pressure tells, and finally a prediction. The order follows when each clue becomes visible and which answers the later clues depend on. Taught in Watching Live: The Master Checklist and Anticipation.
Matchup: The pairing of one offensive player with the defender responsible for him, judged by who should win it. A mismatch is a pairing one side should win clearly, such as a fast tight end covered by a slower linebacker; offenses hunt mismatches and defenses try to avoid them. Taught in The Game Plan: A Week Inside an NFL Building.
Max protect: A protection that keeps seven or eight blockers in to block whatever the defense does (the five linemen plus tight ends and backs, with no check-releases), leaving only two or three receivers in the pattern, usually to buy time for a deep throw. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
MEG: Man everywhere he goes: a cornerback rule in match coverage. The corner covers his receiver man-to-man on every route, short or deep, which frees the defenders who would otherwise help him for other jobs. Taught in Quarters and the Two-High Match Family: Cover 4, Cover 6, Palms.
Mel Blount rule: See Mel Blount rule (1978).
Mel Blount rule (1978): The 1978 NFL rule that lets a defender contact a receiver only within five yards of the line of scrimmage while the quarterback still has the ball; beyond five yards, contact that impedes the receiver is a foul (today called illegal contact). Named for the Pittsburgh cornerback whose physical coverage helped prompt it. Taught in 1978 and the Passing Revolution (1978–1999).
Mesh: A concept in which two receivers from opposite sides run shallow crossing routes that pass within a yard or two of each other over the middle, so defenders chasing them in man coverage run into traffic. Against zone, the crossers settle in the holes. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Middle of field closed: See MOFC.
Middle of field open: See MOFO.
Midline option: An option that reads the first defensive lineman outside the center (often a 3-technique): the back dives at the A gap, and the quarterback gives if that defender stays wide or keeps just outside him if he squeezes the dive. Taught in Option Football: Reading Defenders Instead of Blocking Them.
MIKE ID: See Mike identification.
Mike identification: The pre-snap call, made by the center or quarterback, that names one defender as the ‘Mike’ for this play; every blocker counts his assignment from that man, so all of them block the same picture. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Mike linebacker: The middle linebacker (M), usually the defense’s signal-caller, lined up in the middle of the formation. Taught in The Twenty-Two.
Mint front: See Tite front.
Misdirection: Any play design that gets the defense to commit in one direction, with motion, fakes or the flow of the line, while the ball goes another way. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Mismatch: See Matchup.
MOD: Man only deep: a cornerback rule in match coverage. The corner covers the outside receiver man-to-man if he runs a deep route (anything past about 5 yards), but if the receiver breaks his route off short (about 5 yards or less) the corner passes him to the underneath defenders and drops into his deep zone. Taught in Quarters and the Two-High Match Family: Cover 4, Cover 6, Palms.
MOFC: Middle of the field closed: a defense with one deep safety in the middle of the field (a one-high shell, as in Cover 1 and Cover 3), so the deep middle is guarded. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
MOFO: Middle of the field open: a defense with nobody in the deep middle, usually because two safeties split the field between them (a two-high shell, as in Cover 2 and quarters). Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Motion: One offensive player moving before the snap. At the snap only one player may be moving, he must have lined up in the backfield (not on the line), and he may move parallel to or away from the line of scrimmage, never toward it. Taught in The Pre-Snap Phase.
Motion at the snap: Motion timed so that the player is still moving when the ball is snapped. It describes timing, not a path: jet, orbit, glide, rocket and return motion are usually run this way. NFL rules allow it for one backfield player moving parallel to or away from the line. Taught in Motion and Shifts as Weapons.
Move tight end: A tight end used as a chess piece rather than a fixed position: he lines up next to the tackle on one snap, in the slot or out wide on the next, and in the backfield on a third, so that a defense has to decide before it knows where he will be whether a linebacker (who can tackle him) or a defensive back (who can cover him) is on the field. Aaron Hernandez on the 2010-2012 Patriots and Dallas Clark on the 2000s Colts are the classic examples. Taught in Dynasties and Counterpunches (2000-2016).
Muff: Touching a loose ball, such as a punt, without gaining possession of it. A punt muffed by the receiving team can be recovered by the kicking team, which keeps the ball but may not advance it. Taught in Field Goals, Extra Points, and the Punting Game.
Mug: See Double A-gap mug.
Multiple defense: A defense that lines up in more than one front family (odd and even, three, four and five men on the line), often from the same personnel and sometimes shifting between them before the snap, so its base label says little about what you will see. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Multiplicity (defensive): Building a defense so that one pre-snap picture can become many different plays: several fronts, rushers and coverages that start from the same look and personnel that can play several roles, so the offense learns little before the snap. The opposite of a defense that wins by doing a few things the same way every snap. Taught in Case Study: Fangio’s Two-High Revolution and Macdonald’s Answer.
Mush rush: A deliberately controlled pass rush, used mostly against quarterbacks who run: the ends give up trying to beat their tackles around the corner and instead push them straight back from their outside shoulders, so the pocket is squeezed from all sides rather than raced into. Also called a cage rush. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.

N

Naked bootleg: A bootleg with no blocker assigned to protect the quarterback on the side he rolls to: it depends on the unblocked end chasing the run fake. Taught in Play-Action, Bootlegs, and Screens.
Net punting average: Punting distance after subtracting return yards and 20 yards for every touchback, divided by the number of punts: the field position a punt actually gained, as opposed to how far it flew (gross average). Taught in Field Goals, Extra Points, and the Punting Game.
Neutral situation: A snap on which neither the scoreboard nor the clock forces the play call. The definition this course uses for play-calling tendencies (13-01 and 13-02 use a looser 10-90% band): win probability between 20% and 80% and more than two minutes left in the half; for play-calling tendencies, usually first and second down only. Taught in Tendencies: PROE, Personnel, Motion, and Coverage from Charting Data.
Neutral zone infraction: A defensive foul: before the snap, a defender moves into the neutral zone and either makes a nearby offensive player flinch or gets a free path to the quarterback. The whistle blows at once; five yards. Taught in The Pre-Snap Phase.
Next Gen Stats: The NFL’s player-tracking system, and the league group that turns its data into stats such as separation, completion probability and expected rushing yards, shown on broadcasts and at nextgenstats.nfl.com. Taught in Tracking Data and the Big Data Bowl.
NFL Scouting Combine: The league’s week-long scouting event for more than 300 invited draft prospects, held in Indianapolis each February and March: medical exams, interviews, body measurements and timed drills such as the 40-yard dash, vertical and broad jumps, bench press, three-cone drill and short shuttle. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
nflreadpy: nflverse’s Python package for loading its data, with one function per table (load_pbp(), load_participation(), load_ftn_charting() and so on). It returns Polars data frames and replaced the archived nfl_data_py. Taught in Working with nflverse Data in Python.
nflverse: A volunteer, open-source project that publishes free, cleaned NFL data (play-by-play from 1999, schedules, rosters, participation and charting data) and the R and Python packages that load it. It grew out of nflscrapR and is the home of nflfastR. Taught in Working with nflverse Data in Python.
NGS: See Next Gen Stats.
Nickel: A package with five defensive backs, usually a third cornerback (the nickel back) in place of a linebacker. Named because a nickel is five cents; the NFL’s most-used package. Taught in A First Look at Defense.
Nickel back: See Slot cornerback.
Nickel blitz: A blitz by the nickel back (the slot cornerback), usually off the edge on the slot receiver’s side, with a safety rotating down to take the receiver he left. Many defenses’ code word for the nickel is ‘cat’, hence cat blitz (in some playbooks ‘cat’ means a corner blitz instead). Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
No-huddle: Lining up without a huddle and getting the call to players at the line by words, hand signals, boards or wristbands. Used to play fast, to see the defense before the call is final, or to stop the defense from changing players. Taught in What a Play Really Is.
Nose tackle: The defensive tackle lined up on (or nearly on) the center, usually the biggest player on the defense; in a three-man line, the middle lineman. Taught in The Twenty-Two.
Now screen: A wide receiver screen thrown the instant the ball is snapped: the receiver takes a step back and catches it, with a teammate blocking the nearest defender. Built to punish defenders playing far off. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Nub: A side of the formation where a tight end is the only receiver, with no wide receiver outside him. ‘Trips nub’ puts three receivers on one side and only the tight end on the other. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.

O

OC: See Offensive coordinator.
Odd front: A defensive front with a lineman head-up on the center (a 0-technique nose), so the line is balanced around the ball; the classic odd fronts have three down linemen (the 3-4, which puts five on the line once its two standing outside linebackers are counted) or five (the old 5-2). In an even front, nobody is head-up on the center. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Off coverage: Lining a defender up several yards (usually 5 to 10) away from his receiver, so he can give ground at the snap and keep the receiver in front of him. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Off-schedule play: See Off-script play.
Off-script play: A play that leaves its design: the quarterback escapes the pocket or holds the ball past the play’s timing, and the result depends on improvisation (his and the receivers’ scramble drill) rather than on the called routes. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
Offensive coordinator: The assistant in charge of the offense’s game plan. Often, but not always, the offense’s play-caller. Taught in What a Play Really Is.
Offensive holding: A blocker using his hands or arms to materially restrict a defender: grabbing, hooking, turning or tackling him, or pulling him to the ground, whether his hands are inside or outside the defender’s frame. Ten yards, and a safety if it happens in the offense’s own end zone. Taught in Contact Rules and Penalties as Strategy.
Offensive line: The five players in the middle of the offense (center, two guards, two tackles) who block on every play and may not catch forward passes. Taught in The Twenty-Two.
Offensive pass interference: Contact by an offensive player more than one yard past the line of scrimmage, from the snap until the pass is touched, that hinders a defender: pushing off for separation, or blocking a defender downfield before the pass (an illegal pick). Ten yards from the previous spot. Taught in Contact Rules and Penalties as Strategy.
Offensive system: An offense’s whole way of operating: its play-calling language, its core menu of runs and passes, the rules that adjust those plays to the defense, and the way all of it is taught. Coaches carry their system from team to team. Taught in Offensive Systems and Play-Calling Languages.
Offset back: A running back or fullback aligned to one side of the quarterback rather than straight behind him. A back beside a shotgun quarterback is often called a ‘sidecar’. Taught in Formation Rules and the Language of Alignment.
Offset I: An I-formation in which the fullback lines up a yard or two to one side, behind a guard or tackle, instead of directly behind the quarterback, to give him a better angle to where he will block. Offset toward the tight end it is often called a Strong I; offset away from him, a Weak I. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Offside: Being in or beyond the neutral zone when the ball is snapped. Either team can be offside, but it is almost always a defender. The play goes on, and the other team can take the result or the five yards. Taught in The Pre-Snap Phase.
On schedule / behind schedule: On schedule: early-down gains that leave a manageable next down, roughly 4 or more yards on first-and-10 and then a little more than half of what is left on second down, so that third down is short or never comes. Behind schedule: the opposite, after a short gain, a loss, a sack, an incompletion or a penalty leaves second-and-long or third-and-long. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
On the line / off the line: Where an offensive player stands at the snap. On the line means level with the center (by rule, the helmet breaks a plane through the center’s waist). Off the line means in the backfield, at least a yard behind the line. At least seven players must be on it; a player in between is illegal. Taught in Formation Rules and the Language of Alignment.
One-cut runner: A running back who presses the aiming point, makes a single decisive cut and goes straight upfield, rather than dancing or bouncing around in the backfield. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
One-gap: A style of defensive line play in which each lineman is responsible for a single gap: he lines up in or shaded toward it, attacks it at the snap, and leaves the other gaps to his teammates. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
One-high: A coverage shell with one safety deep in the middle of the field; the other safety plays closer to the line of scrimmage. Taught in A First Look at Defense.
Onside kick: A short kickoff that the kicking team tries to recover itself once the ball has gone the required 10 yards. In the NFL it must now be declared to the officials in advance. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Open field: The middle of the field, roughly your own 25 to the opponent’s 40, where field position neither forces the offense’s hand nor tempts it, and the whole playbook is available. Most snaps of most games happen here. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
Opening script: A list of plays, usually about 15 and sometimes 20 or more, that the play-caller decides before the game to call in order at the start, on ordinary first and second downs: to test how the defense lines up, to settle the players, and to get the week’s best ideas called before the emotion of the game takes over. Taught in The Game Plan: A Week Inside an NFL Building.
OPI: See Offensive pass interference.
Opponent adjustment: Correcting a team’s or player’s numbers for the strength of the opponents faced, so that a good day against a strong defense counts for more than the same day against a weak one. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Option: A play on which the offense deliberately leaves a defender unblocked and the quarterback decides after the snap, from what that defender does, who carries the ball; the read does the work of a blocker. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Option route: A route on which the receiver picks the finish after the snap from what the coverage does: against man he breaks away from the defender’s leverage; against zone he settles in the hole between defenders. The quarterback has to see the same thing. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Orbit motion: Motion that loops behind the quarterback: a receiver comes in toward the ball, swings around behind the quarterback (and the back), and is still moving toward the far side at the snap. Taught in Motion and Shifts as Weapons.
Orientation vs direction: Two different angles in tracking data. Orientation (o) is the way a player’s shoulders face; direction (dir) is the way he is moving. They differ whenever a player backpedals, shuffles or drops back. Taught in Tracking Data and the Big Data Bowl.
Out: A route that runs straight upfield, then breaks flat toward the sideline: a quick out at about 5 yards, a deeper out at 10–14 yards (the 5 in many route trees). Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Out-of-bounds clock rule: When a runner goes out of bounds, the game clock normally restarts as soon as the ball is re-spotted and the referee signals ready for play; after the two-minute warning of the first half and in the last five minutes of the game it stays stopped until the next snap. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Outside linebacker (3-4): See Stand-up edge.
Outside zone: A zone run aimed at or just outside the tight end, in which the line steps laterally to get the defense running sideways and the back makes one cut into the first crease. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Overhang defender: The defender (usually a nickel back, outside linebacker or safety) who stands outside the box but inside a slot receiver, responsible both for the edge of the run and for the short pass outside him. Taught in A First Look at Defense.
Overhanger: See Overhang defender.
Overload blitz: A blitz that sends more rushers at one side of the protection than the blockers on that side can handle, so that one of them comes free there even when the offense has enough blockers in total. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Overtime rules: The NFL’s rules for a game tied after four quarters. Since 2022 in the playoffs and 2025 in the regular season, both teams get a chance to possess the ball (unless the kicking team scores a safety on the first possession) and the next score wins after that. Regular-season overtime is one 10-minute period and can end in a tie; playoff overtime continues in 15-minute periods until there is a winner. Taught in The Clock, the Two-Minute Drill, and Fourth Down.

P

Pace: How many offensive plays a team runs, usually counted as plays per game (in 2025, from about 55 to about 65); sometimes measured as seconds between plays in neutral situations, which strips out the effect of the score. More plays means more chances for every player on the offense. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Packaged play: A single play call that bundles a run with one or more pass routes (or two runs and a pass), with rules that tell the quarterback which part to use against what he sees. Every RPO is a packaged play; the term is older and broader. Taught in Run-Pass Options: Plays That Are Two Plays.
Palms: A two-high coverage played on one side of the field in which the cornerback and safety trade jobs when the inside receiver (#2) breaks out quickly: the corner jumps (traps) #2’s short out or flat route and the safety takes the outside receiver (#1) deep. If #2 goes vertical, the safety carries him and the corner plays #1 man to man. Taught in Quarters and the Two-High Match Family: Cover 4, Cover 6, Palms.
Participation data: nflverse’s per-play table of who was on the field: offensive and defensive personnel, the formation, defenders in the box and, for most dropbacks from 2018 on, the coverage. Next Gen Stats supplied 2016-2022 and FTN supplies 2023 on; each season is published only after it ends. Taught in Working with nflverse Data in Python.
Pass concept: A set of routes designed to work together on one pass play, usually by putting one or two defenders in a position where whatever they do leaves a receiver open. Concepts have names (smash, flood, mesh) so the whole offense can learn one word instead of five routes. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Pass rate over expected: See PROE.
Pass rush win rate: ESPN’s measure, built from NFL Next Gen Stats tracking data, of how often a pass rusher beats his block within 2.5 seconds of the snap; the fixed clock keeps the quarterback’s habits out of the number. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Pass-off (switch vs stay): How two adjacent blockers handle a stunt. Switch: each keeps his area and takes whoever comes into it, handing the first rusher to his neighbor. Stay: each follows the man he started on, wherever he goes. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Pass-rush game: See Stunt.
Passer rating: The NFL’s official passing formula since 1973: completion rate, yards per attempt, touchdown rate and interception rate, each capped and combined onto a scale from 0 to 158.3. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
PAT: See Extra point.
Pattern matching: Zone coverage in which defenders read the receivers’ routes as they develop and pick up, man to man, whoever enters or stays in their area, passing receivers from one defender to the next by rule. Most NFL zone coverage today matches to some degree. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
pbp: See Play-by-play.
Penetration: A defender getting across the line of scrimmage and into the offense’s backfield fast, through a gap, to disrupt a play before it develops; the aim of one-gap line play. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Personal protector: The punt team’s last blocker and on-field leader, standing about five to seven yards behind the line: he calls the protection, blocks any rusher who gets through, and is a common ball carrier on fake punts. Taught in Field Goals, Extra Points, and the Punting Game.
Personnel grouping: The mix of running backs, tight ends and wide receivers an offense has on the field for a play, written as two digits: running backs first, tight ends second, so ‘12’ means one back and two tight ends (and therefore two wide receivers). Taught in Personnel: Who’s on the Field Before Anything Else.
PFF grade: Pro Football Focus’s proprietary player grade: analysts watch every snap, score each player’s performance on it, and scale the season’s scores to 0-100. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Philly Special: The trick play the Eagles ran for a touchdown on fourth-and-goal in Super Bowl LII (February 2018): the quarterback walks up behind the line as if changing the play, the ball is snapped directly to the running back, who pitches it to a tight end on a reverse, and the tight end throws to the quarterback, who has slipped uncovered into the end zone. Taught in Case Study: The Eagles — Trenches, RPOs, and the Tush Push.
Pick route: See Rub route.
Pin-and-pull: An outside-run blocking scheme in which each lineman with a defender in his backside gap blocks down on him (pins him) and each lineman without one pulls around to lead, so no one has to reach a defender lined up outside him. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Pistol: A hybrid alignment: the quarterback about four yards behind the center and the running back directly behind him, so the back can run straight ahead to either side. Taught in Formation Rules and the Language of Alignment.
Pistol option offense: An offense that makes the pistol its base alignment and builds its run game on the quarterback as a runner: option reads (zone read, bash, power read, counter read) and designed quarterback runs, usually with tight ends and fullbacks as extra blockers, so that the defense must account for one more ball carrier on every snap. The 2019–2022 Baltimore Ravens under Greg Roman are the NFL’s defining example; Chris Ault’s Nevada teams built the college version. Taught in Case Study: The Ravens’ Option Run Game with Lamar Jackson (2019–2025).
Pitch: A one-handed underhand toss sideways or backward from the quarterback to a trailing back on an option play; also the name of the trailing back’s role (the pitch man). A pitch that is dropped is a live ball. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Platoon football: Using separate groups of players for offense and defense (later also for special teams and for particular situations), which became possible once the rules allowed free substitution: permanently in the NFL from 1950. Before it, the same eleven men played both ways. Taught in From the Single Wing to the 1970s Scoring Drought (1906–1977).
Play call: The instruction a team uses for one snap: usually a string of code words naming the formation, any motion, the protection and the play itself. Taught in What a Play Really Is.
Play clock: The countdown between plays: 40 seconds from the end of the last play, or 25 after certain stoppages. The offense must snap the ball before it reaches zero. Taught in The Game in Fifteen Minutes.
Play-action: A pass play that begins with a fake run, usually a fake handoff to a running back, so that linebackers and safeties step toward the line before they realize it is a pass. Taught in Play-Action, Bootlegs, and Screens.
Play-by-play: A dataset with one row for every play of every game (plus bookkeeping rows such as timeouts and the ends of quarters) that records the situation before the snap, what happened, who was involved, and model values such as expected points and win probability. nflverse’s version starts with the 1999 season. Taught in Working with nflverse Data in Python.
Play-caller: The one coach who actually chooses each play during the game and sends it in. Can be the head coach or a coordinator. Taught in What a Play Really Is.
Playbook: The full catalog of a team’s plays and the rules for running them. Each week’s game plan is chosen from it. Taught in What a Play Really Is.
Playside / backside: The play side is the half of the formation the run is aimed at; the backside (or back side) is the other half, away from the play. Blockers’ jobs differ by side: create the hole on the play side, stop pursuit on the backside. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Plug: A linebacker stepping straight forward into a gap directly in front of him, usually an inside gap that a defensive lineman has slanted out of, and closing it with his body. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Plus territory: The opponent’s half of the field. Coaches write yard lines there with a plus sign (‘plus 35’ is the opponent’s 35) and yard lines in their own half with a minus sign (‘minus 25’ is their own 25), so ‘minus territory’ is the offense’s own half. Taught in Early Downs and Field Zones: How Situation Shapes the Call.
Plus-one: Having one more run defender than the offense has blockers, so one defender is free to make the tackle. Defenses usually get it by bringing a safety down; offenses erase it with an extra blocker, a quarterback read or a pass. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Poach: A check against a 3x1 formation in which the backside safety leaves the lone receiver to his cornerback and works across the field to take the trips side’s inside receiver (#3) if he goes deep. Taught in Disguise, Rotation, and Split-Field Coverage.
Pocket: The protected space the blockers form around the quarterback on a pass: a cup with the interior linemen holding firm in front and the tackles giving ground on the sides. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Point of attack: The spot along the line where a run is designed to hit, such as the right B gap. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Point per reception: See PPR.
Point spread: The betting market’s estimate of a game’s winning margin: a team listed at −7 is expected to win by about seven points. With the game’s total (over/under), it gives each team an implied team total and forecasts the game script before kickoff. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Pooch punt: A deliberately short, high punt from near midfield or closer, aimed to land inside the opponent’s 10-yard line without bouncing into the end zone. Taught in Field Goals, Extra Points, and the Punting Game.
Pop pass: A quick throw to a tight end (or a back or slot receiver) who starts as if run blocking, then releases into the space behind linebackers who have stepped up to stop the run. Often the pass branch of an RPO. Taught in Run-Pass Options: Plays That Are Two Plays.
Position coach: An assistant who teaches one position group (quarterbacks, offensive line, linebackers and so on) its technique and assignments. Taught in What a Play Really Is.
Positional value: How much a position, as opposed to a particular player, contributes to winning, and so how much a team should be willing to pay or draft for it. Quarterback is far ahead of everything else; edge rusher and wide receiver come next, then interior pass rushers, offensive tackles and cornerbacks; running back, off-ball linebacker, safety and tight end are near the bottom. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Possession: Control of the ball. The team that has it is the offense; one unbroken stretch of having the ball is also called a possession. Taught in The Game in Fifteen Minutes.
Post: A route that pushes upfield, then angles deep toward the middle of the field, where the goalposts are (the 8 in many route trees). Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Post-snap rotation: Defenders, usually the safeties, moving at or just after the snap from the shell they showed into a different one: two-high into one-high, or one-high into two-high. Taught in Disguise, Rotation, and Split-Field Coverage.
Post-snap RPO: An RPO decided after the snap: the line blocks the run, the quarterback holds the ball at the mesh with the running back and watches one defender; if that defender plays the run, he throws behind him, and if he plays the pass, he hands off. Taught in Run-Pass Options: Plays That Are Two Plays.
Post-wheel: A two-receiver concept on one side: the outside receiver runs a post toward the middle and the inside receiver (or a back) runs a wheel up the sideline, splitting the defenders on that side inside and outside: the cornerback who carries the post, and the shallow defender who can’t run with the wheel. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Power: The signature gap-scheme run: the play-side linemen block down, the fullback or H-back kicks out the end man, and the backside guard pulls through the hole to lead on the play-side linebacker, while the backside end is left unblocked. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Power I: An I-formation with a third back lined up beside the fullback, giving the offense two lead blockers in front of the tailback (usually 31 personnel). A short-yardage and goal-line formation. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Power O: See Power.
Power read: See Inverted veer.
PPR: Point per reception: a fantasy scoring format that adds one point for every catch on top of the points for yards (one per 10) and touchdowns (six). Half-PPR adds half a point a catch; standard (non-PPR) scoring adds nothing. PPR raises the value of pass-catching running backs and high-volume, short-area receivers relative to touchdown-dependent players. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Practice squad elevation: Moving a practice-squad player up to the game-day roster for one game, after which he returns to the practice squad without being exposed to waivers. A team may elevate two players a game, and each player at most three times a season. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Pre-snap read: The quarterback’s look at the defense’s alignment before the snap (leverage, cushion, the safeties, the box) that tells him which side or which receiver a play should go to. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Pre-snap RPO: An RPO decided before the ball is snapped: the quarterback counts defenders (in the box, and over the receivers) and checks leverage, then hands off or throws to the side the numbers favor, without reading anyone after the snap. Taught in Run-Pass Options: Plays That Are Two Plays.
Prediction log: Your running record of pre-snap calls: for each snap, the situation, your guess (run or pass, later more), how confident you were, the main clue, and what actually happened. Scored to see whether your reading is getting better. Taught in How to Watch a Broadcast Like You Mean It.
Press: Lining a cornerback (or another defender) up within about a yard of a receiver, to jam him with the hands at the snap and knock his route off its timing. Contact is legal only until the receiver is 5 yards past the line of scrimmage. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Pressure: A pass rusher forcing the quarterback to change what he wanted to do: a sack, a hit, or a hurry. Definitions differ by data provider. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Pressure look: A pre-snap alignment that shows more possible rushers than the offense can comfortably block (linebackers walked up into the A gaps, a safety or nickel back creeping toward the line), whether or not they will rush. Its job is to force the offense’s protection and hot-throw decisions before the snap. Taught in Zone Blitzes, Fire Zones, and Simulated Pressure.
Pressure rate: Pressures divided by dropbacks: the share of pass plays on which the quarterback was pressured. A more stable measure of protection (or pass rush) than sacks. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Prevent defense: A defense, used when protecting a lead in the last seconds of a half, that rushes three or four and drops seven or eight defenders deep, conceding short completions in front of it in order to take away anything long and to tackle the catch in bounds. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Pro day: A workout held at a college campus in March and April for that school’s draft prospects, attended by NFL scouts and coaches; players who skipped or could not finish the combine drills run them here, usually on their own turf and often with friendlier timing. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Pro set: A two-back formation with the quarterback under center and the halfback and fullback side by side behind him, usually with a tight end, a flanker and a split end (21 personnel). The standard NFL formation of the 1950s to the 1970s. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
PROE: Pass rate over expected: how much more or less often a team passed than its situations predicted, the average over its snaps of ‘passed (1 or 0) minus xpass’, in percentage points. Usually measured in neutral situations on first and second down, where the play-caller has a real choice. Taught in Tendencies: PROE, Personnel, Motion, and Coverage from Charting Data.
Progression: The order in which the quarterback looks at his receivers on a pass play, usually tied to the steps of his drop: if the first is covered he moves to the second, and so on down to the checkdown. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Proper scoring rule: A way of scoring probability forecasts whose expected score is best when you state exactly the probability you believe, so it can’t be gamed by shading numbers up or down. The Brier score and log loss are proper. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
PRWR: See Pass rush win rate.
Pull: A lineman leaving his spot at the snap and running laterally behind the line to block somewhere else, usually to add a blocker at the point of attack. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Puller: The lineman (or lineman pair) who pulls on a given play, usually from the backside, to kick out the end man or lead through the hole; the defense’s best clue to where a gap run is going. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Punch: A pass blocker’s short, two-handed strike into the rusher’s chest, inside his frame, to stop his momentum and win control of his body. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Punt: A kick, almost always on fourth down, that gives the ball to the other team on purpose in exchange for pushing them back down the field. Taught in Downs, Distance, and Field Position.
Punt block: A return-team call that sends extra rushers, often overloading one side, to block the punt instead of returning it; rushers aim at a spot about a yard in front of the punter where the ball leaves his foot, not at the punter himself. Taught in Field Goals, Extra Points, and the Punting Game.
Punt safe: A return-team call for when a fake is likely: the defense keeps (or sends on) its regular defenders, covers every eligible receiver and the likely ball carriers, and gives up most of the return to make sure the kicking team doesn’t keep the ball. Taught in Field Goals, Extra Points, and the Punting Game.
Punter: The specialist who punts the ball away on fourth down, standing about 15 yards behind the line. Taught in The Twenty-Two.
Pursuit angle: The path a defender takes to a ball carrier who is already moving: aimed at where the runner will be rather than where he is, and kept slightly inside him so that he cannot cut back, so that the defender meets the runner instead of chasing him. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Push rule: See Assisting the runner.

Q

QB counter: A designed quarterback run with counter blocking: the quarterback steps one way, then follows two linemen pulling the other way, one kicking out the end and one leading through the hole. Taught in Option Football: Reading Defenders Instead of Blocking Them.
QB draw: A designed quarterback run that starts as a pass: the line pass-blocks, the quarterback shows a drop, then runs up the middle once the rushers have gone upfield and the coverage has turned to the receivers. Taught in Option Football: Reading Defenders Instead of Blocking Them.
QB hit / hurry: Two kinds of pressure short of a sack. A hit is contact that knocks the quarterback down or hits him as he throws; a hurry forces him to throw early or move off his spot without being hit. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
QB power: A designed quarterback run blocked like the power play: the backside guard pulls through the hole and the running back, no longer the ball carrier, becomes a lead or kick-out blocker. Taught in Option Football: Reading Defenders Instead of Blocking Them.
QB sneak: A designed run in which the quarterback takes the snap under center and immediately drives forward behind his center, usually to gain a yard or less. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
QB spy: See Spy.
QB sweep: A designed quarterback run to the outside, with pulling linemen or the running back leading him around the edge. Taught in Option Football: Reading Defenders Instead of Blocking Them.
QBR: ESPN’s proprietary quarterback rating (0 to 100, with 50 about average), built on expected points and win probability and crediting the quarterback’s share of every play, including runs, sacks and penalties. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
QC coach: See Quality control coach.
Quads: Four receivers on the same side of the ball. Because only five players can be eligible, quads leaves at most one receiver on the other side. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Quality control coach: An entry-level assistant who breaks down film and data into scouting reports and tendency lists for the coordinators. Taught in What a Play Really Is.
Quarter: One of the four 15-minute periods of game-clock time in an NFL game. Teams switch ends after the first and third. Taught in The Game in Fifteen Minutes.
Quarter (package): A package with seven defensive backs, for desperate passing situations such as a last-second throw to the end zone. Some staffs call it dollar, and some use dollar for other defensive-back-heavy packages. Taught in A First Look at Defense.
Quarterback: The offensive player who takes the snap on almost every play, hands the ball off or throws it, and usually relays the play call and makes the pre-snap adjustments. Taught in The Twenty-Two.
Quarters: A two-deep zone coverage in which the two cornerbacks and the two safeties each start with a deep quarter of the field but play it with match rules: each corner takes the outside receiver (#1) if he goes deep, each safety reads the inside receiver (#2) and also helps against the run. Only three defenders are left underneath. Taught in Quarters and the Two-High Match Family: Cover 4, Cover 6, Palms.
Quick game: Pass plays built to get the ball out in roughly 2.5 seconds or less: a short drop, short routes and a throw timed to the receiver’s break. Used to beat pressure, stay ahead of the down and distance, and stretch the run game sideways. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Quick screen: See Now screen.

R

RAS: Relative Athletic Score: Kent Lee Platte’s 0-to-10 summary of a prospect’s measurements and drills, each converted to a percentile against every player measured at his position since 1987 and then combined. A 5 is average for the position, a 9 or above elite. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Rat: See Robber.
Rat zone: See Hole zone.
RB screen: See Slow screen.
Reach block: A block on a defender lined up on your play-side shoulder or in your play-side gap, in which you get your head and body outside him to seal him inside, away from the play. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Reach-and-overtake: A two-man outside-zone block: the play-side lineman of the pair gets his hands on a defender to stop him running wide, his neighbor races flat to take the defender over, and the first lineman climbs to a linebacker. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Read (post-snap): A decision a player makes after the snap by watching one particular defender or area: ‘if he does this, I do that.’ Taught in What a Play Really Is.
Read defender: See Read key.
Read key: The defender an option play leaves unblocked and the quarterback watches after the snap; what he does decides whether the quarterback gives, keeps or pitches. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Read option: See Zone read.
Read safety: A safety whose job is decided after the snap by one key receiver, usually the inside receiver on his side (#2): he covers #2 if #2 goes deep, helps on the outside receiver if #2 goes short or out, and comes down to fit the run if #2 blocks. The quarters safety is the classic read safety. Taught in Quarters and the Two-High Match Family: Cover 4, Cover 6, Palms.
Read-option wave (2012): The 2012 NFL season’s burst of zone-read and pistol option offense built around young running quarterbacks (Robert Griffin III in Washington, Colin Kaepernick in San Francisco, Russell Wilson in Seattle and Cam Newton in Carolina). It was concentrated in a handful of teams and faded within two seasons as defenses learned to play the read and the quarterbacks were hurt or changed their game; designed quarterback runs came back, league-wide, from 2018. Taught in Dynasties and Counterpunches (2000-2016).
Receiver numbering: Counting a formation’s receivers from the sideline in, separately on each side: the widest is #1, the next #2, then #3. Defenses assign coverage by these numbers rather than by names. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Red zone: The area inside the opponent’s 20-yard line. The field is compressed there, and drives that reach it usually end in a touchdown or a field goal. Taught in Downs, Distance, and Field Position.
Red-zone share: A player’s share of his team’s opportunities (carries plus targets) inside the opponent’s 20-yard line, where most touchdowns are scored. Inside-the-10 and inside-the-5 versions narrow it further toward the goal line. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Reduced front: A front in which the defensive linemen on one side (or both) slide a gap inward from their usual spots, for example an end moving from a 5-technique to a 3 or a 4i, with an edge player on the line outside them to take the outside gap; the 4-3 Under is the classic one-side reduction and the tite front reduces both sides. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Reduced split: A receiver lined up closer to the formation than his normal landmark, inside the numbers. A common clue to a block on the inside or a route breaking toward the sideline. Taught in Formation Rules and the Language of Alignment.
Referee: The crew chief of the seven NFL officials, the only one in a white cap. He stands 10 to 12 yards behind the line in the offensive backfield, on the side of the quarterback’s throwing arm, watches the quarterback and hits on him, rules on the quarterback’s fumbles and passes, and announces every foul and replay result over his microphone. Taught in Officiating, Replay, and the Rules of the Ball.
Relative Athletic Score: See RAS.
Release (vs press): A receiver’s first moves off the line against a defender pressing him: footwork and hand-fighting that get him past the jam and onto his route without being knocked off it. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Replay assist: The replay booth’s quick help to the on-field crew, before the next snap and usually with no stoppage, on clear-cut objective facts (possession, the spot relative to a line, whether a pass was caught, whether a player was down or out of bounds, the clock), used since 2021. Since 2024 it may also wipe out certain flags when clear video shows the objective element of the foul didn’t happen (no contact with the passer’s head or neck on roughing the passer, the passer outside the pocket on grounding, the runner still in bounds on a late hit, from 2024; face mask, horse-collar, tripping, hits to a defenseless player’s head or neck and roughing or running into the kicker added in 2025), but it cannot add a foul nobody called. Since 2026 league officiating staff may also consult on ejections for flagrant acts. Taught in Officiating, Replay, and the Rules of the Ball.
Replay review: Checking an on-field ruling against video. The ruling is reversed only if the video shows clear and obvious evidence that it was wrong; otherwise it ‘stands’ (not enough evidence either way) or is ‘confirmed’ (the video supports it). Since 2017 the final decision in the NFL is made in New York, by the league’s senior vice president of officiating or a designee, consulting the replay official and the referee. Taught in Officiating, Replay, and the Rules of the Ball.
Reporting eligible: How a player wearing a lineman’s number (50-79) becomes an eligible receiver for a play: he tells the referee before the snap, the referee announces it so the defense knows, and he lines up at the end of the line or in the backfield. Taught in Formation Rules and the Language of Alignment.
Resolution: How much a forecaster’s stated probabilities sort events apart: different numbers on different occasions, with the higher numbers really coming true more often. One of the three parts of the Brier score; it’s the part that rewards knowing more, where calibration rewards knowing how sure to be. Taught in Film Study: All-22, Charting a Game, and Scoring Yourself.
Restraining line: The line a team may not cross before a free kick is made. Under the dynamic kickoff the kicking team’s is the receiving team’s 40 and the receiving team’s is its own 35. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Restricted free agent: A player whose contract has expired after exactly three accrued seasons. If his team offers him a qualifying one-year ‘tender’, he may negotiate with other teams, but his old team may match any offer sheet he signs or, depending on the tender, take a draft pick as compensation. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Return motion: Motion that goes one way and then reverses back toward where it started, usually at or just before the snap. It makes a defender who followed the first move stop and restart, and lets the offense watch the defense react twice. Taught in Motion and Shifts as Weapons.
Return unit: The receiving team’s eleven on a kickoff (or a punt): the returner or returners and the players who block for them. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Return wall: A punt return in which most of the return team peels back to one sideline and forms a line of blockers parallel to it, about five yards apart, and the returner runs behind that wall. Taught in Field Goals, Extra Points, and the Punting Game.
Returner: The player on the receiving team who catches a kickoff or punt and tries to run it back. Taught in The Twenty-Two.
Reverse: A run in which the ball is first given to a player running one way and then handed or pitched to a teammate running the other way, so the ball changes direction behind the line. Two exchanges; a double reverse adds a third. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
RFA: See Restricted free agent.
Rhythm throw: A pass thrown on the quarterback’s last step of his drop, with no hitch or hesitation, so the ball arrives just as the receiver breaks. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Rip move: A pass rush move in which the rusher drives his inside arm up under the blocker’s arm and through his armpit, like an uppercut, to lift the blocker’s arm away and get his own hips past him; the usual finish of a speed rush. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Rip/liz motion: See Short motion.
Robber: A defender with no receiver to cover in man coverage (usually a safety) who sits in the middle of the field about 8 to 12 yards deep, reads the quarterback, and drives on in-breaking throws such as digs, crossers and slants. Many playbooks call him the rat, especially when he is a linebacker sitting lower, in the hole. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Rock motion: See Rocket motion.
Rocket motion: A fast motion by a back, deep in the backfield and straight out toward the sideline, so he is already running wide at the snap. The classic play is the rocket toss, a pitch to him at the edge. Taught in Motion and Shifts as Weapons.
Rookie wage scale: The fixed pay system for drafted rookies, introduced in the 2011 collective bargaining agreement: every draft slot carries a set four-year contract value, falling steeply from the first pick to the last, with little room to negotiate. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Rookie-contract window: The years in which a team’s good young player, above all a quarterback, is still on his cheap rookie deal. The gap between his pay and what a veteran of his quality costs is money the team can spend elsewhere, and the window closes when he signs his second contract. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Roughing the passer: An unnecessary or dangerous hit on a quarterback who is passing or has just thrown: a hit after the ball is clearly gone, forcible contact to his head or neck, a hit at or below the knees, or landing on him with all or most of the defender’s body weight. Fifteen yards and an automatic first down. Taught in Contact Rules and Penalties as Strategy.
Route conversion: A rule built into a route that changes it according to the coverage: for example, a seam route that stays straight against one deep safety but bends into the open middle against two. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Route participation: The share of a team’s pass plays (dropbacks) on which a player runs a pass route. It is lower than his snap share whenever he is on the field but blocking, so it separates a tight end who stays in to protect from one who goes out for passes. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Route tree: A numbered menu of the basic routes a receiver can run, drawn as branches off one straight stem. In a common version, 1 to 9 run from the flat to the go, odd numbers break toward the sideline, even numbers toward the middle, and the numbers roughly grow with depth. Numbering varies by team. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
RPO: Run-pass option: a play on which the line blocks a run and the quarterback decides, before or just after the snap, whether to hand the ball off or throw a quick pass, by counting the defense or reading one defender who cannot defend both. Taught in Run-Pass Options: Plays That Are Two Plays.
RSWR: See Run stop win rate.
Rub route: A route designed to cross close to a teammate’s route, so a defender chasing one of the receivers has to go around the other. Legal while the receiver simply runs his route; when he deliberately blocks a defender more than a yard past the line of scrimmage, from the snap until the pass is touched, it is an illegal pick (offensive pass interference). Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Rugby punt: A punt kicked on the run after the punter rolls out toward one side, usually as a low, end-over-end kick that bounces and rolls; it buys time against the rush, makes the ball hard to field, and can turn into a run if the edge is open. Taught in Field Goals, Extra Points, and the Punting Game.
Run fit: A defense’s plan for which defender takes which gap or job against a run, and each defender getting there after the snap; to ‘fit’ a run is to arrive in your assigned gap, on the correct side of your blocker. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Run stop win rate: ESPN’s tracking-based rate of how often a defender beats his block quickly on run plays; the run-defense companion to pass rush win rate. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Run-and-shoot: A four-receiver passing offense (two wide receivers, two slot receivers, one back, no tight end) built on a handful of plays in which most routes are chosen after the snap from what the coverage does. Popularized by Mouse Davis and June Jones. Taught in Offensive Systems and Play-Calling Languages.
Run-pass option: See RPO.
Run-through: A linebacker attacking through his gap at the snap, or on his first key, instead of waiting: he beats the climbing blocker to the spot and meets the play in the backfield. Fast and disruptive, but exposed to misdirection. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Running back: The offensive back whose main job is to carry the ball on running plays; he also catches short passes and blocks blitzers. Lines up behind or beside the quarterback. Taught in The Twenty-Two.
Rush lane: The path to the quarterback that each rusher in a four-man rush is responsible for; if every rusher stays in his lane, the quarterback has no gap to step up or escape through, and if one leaves his lane, a hole opens. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Rush plan: A pass rusher’s planned sequence of moves across a game: show one move until the blocker adjusts to stop it, then use the counter his adjustment opens. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Rush three, drop eight: A pass defense that sends only three pass rushers and puts eight defenders in coverage, usually on third-and-long, to crowd the throwing windows at and past the line to gain and make the quarterback hold the ball. Taught in Third Down: The Money Down.
Rush yards over expected: See RYOE.
RYOE: Rush yards over expected: a runner’s actual rushing yards minus the yards a tracking-data model expected from where the blockers and defenders were when he took the handoff. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.

S

Sack: Tackling the quarterback, or forcing him out of bounds, behind the line of scrimmage on a pass play before he can throw. The offense loses the yards and uses up a down. A quarterback stopped behind the line on a designed run is simply tackled for a loss. Taught in Downs, Distance, and Field Position.
Safety (position): A defensive back who lines up deepest, usually 10 to 15 yards off the ball, as the last line of defense against deep passes and long runs. Taught in The Twenty-Two.
Safety (score): Two points for the defense when the offense’s ball carrier is downed in his own end zone (or the offense fouls there). The team scored on must then kick the ball away from its own 20. Taught in The Game in Fifteen Minutes.
Safety blitz: A blitz in which a safety rushes the quarterback, usually timing a walk or run down from depth so that he reaches the line at full speed just as the ball is snapped, while the other safety rotates to the deep middle. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Sail: See Flood.
Salary cap: A hard limit, the same for every team, on what a club may count against its player payroll in a season, set each year from a share of league revenue. The NFL’s began in 1994 at $34.6 million per team. Taught in 1978 and the Passing Revolution (1978–1999).
Sam linebacker: The strong-side linebacker (S), lined up on the tight end’s side of the formation; usually the biggest linebacker, often the one taken off the field for a fifth defensive back. Taught in The Twenty-Two.
Scat protection: A protection in which the running back lines up in the backfield but releases into his route at once instead of checking a blitzer first, so the line blocks and the quarterback is responsible for any extra rusher; the exact meaning of the word varies by playbook. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Scheme fit: How well a player’s body type and skills match what a particular scheme asks of his position, which makes the same player worth more to one team than another: a lighter, quick guard for a wide-zone team, a bigger drive blocker for a gap team; a heavy two-gap nose for some 3-4 defenses, a quick one-gap 3-technique for an attacking four-man front; a long press corner or a quick off-coverage corner. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Scissors: A two-receiver deep concept on one side in which the outside receiver runs a post and the inside receiver a corner route, so their paths cross (like the blades of scissors). Built to beat two-high coverages such as Quarters, by making the safety and the cornerback cross each other and lose their leverage. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Scramble: A quarterback who drops back to pass, finds no one open and runs with the ball. nflverse files it as play_type ‘run’ with qb_scramble = 1 and pass = 1, so it counts as a pass under the pass flag. Taught in Working with nflverse Data in Python.
Scramble drill: The offense’s practiced rules for what receivers do when the quarterback leaves the pocket and is still looking to throw: short routes go deep, deep routes come back toward him, receivers work toward the side he runs to, spread out at different depths, and get into his line of sight. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
Scrape: A linebacker running sideways behind his own defensive linemen (‘over the top’ of them) to a gap farther outside, staying square and a step behind the ball, so he can fill as soon as the run commits. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Scrape exchange: A defensive answer to the zone read in which the unblocked end crashes down on the running back and a linebacker loops around him to take the quarterback, so that the quarterback’s ‘keep’ runs into the linebacker. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Screen: A pass thrown to a receiver at or behind the line of scrimmage with blockers already set up in front of him. The defense is invited to rush or flow one way; then the blockers release to the other. Taught in Play-Action, Bootlegs, and Screens.
Seal block: A block whose job is to wall a defender off from the ball carrier’s path rather than to move him: usually pinning an inside defender inside so the run can go outside him. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Seam: A vertical route up the seam, the strip of field between the hash marks and the painted numbers, usually by a slot receiver or tight end, aimed at the gaps between deep defenders. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Seam-flat defender: An outside underneath defender whose first job is the number 2 receiver’s vertical route up the seam (he walls it off or carries it), and who works to the flat only once the seam is gone. The match-Cover 3 and zone-blitz version of the curl-flat defender. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.
Secondary: The defensive backs as a group (cornerbacks and safeties), who line up farther from the ball and are responsible first for pass coverage. Taught in The Twenty-Two.
Self-scout: A team’s study of its own film and data, the way an opponent would study it, to find the tendencies it is giving away and decide which to break, which to hide and which to keep as bait. Taught in Constraint Theory: How Plays Talk to Each Other.
Separation: The distance from a receiver to the nearest defender. Next Gen Stats measures it at the moment the ball arrives (the catch or the incompletion). Taught in Tracking Data and the Big Data Bowl.
Sequencing: Calling plays in a deliberate order so that each one sets up a later one: show the defense a look, watch how it reacts, then call the play that beats that reaction. Taught in Constraint Theory: How Plays Talk to Each Other.
Series football: Building an offense from groups of plays that begin with the same backfield action and end differently, each one designed to beat the defense’s reaction to another, so the defense cannot tell which play it is from the first second. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Set: The moment, required before every snap, when all eleven offensive players are stationary at the same time. NFL rules require that they hold it for at least one full second. Taught in The Pre-Snap Phase.
Set the edge: The job of the outermost defender at the line on a run toward him: take on the blocker at or near the line of scrimmage with his outside arm free, so the run cannot get outside him and the ball carrier has to turn back inside toward teammates. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Setup zone: Under the dynamic kickoff, the five-yard strip between the receiving team’s 30 and 35 where at least nine of its players line up before the kick. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Shade: Lined up on one shoulder of an offensive lineman rather than head-up, which usually means the defender is responsible for the gap on that side. Also used as a noun for such a defender (‘a shade nose’). Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Shadow corner: A cornerback assigned to follow one receiver (usually the opponent’s best) wherever he lines up, left, right or in the slot, instead of staying on one side of the field. Taught in Man Coverage: Cover 0, Cover 1, Robbers, and Brackets.
Shallow cross: A concept built around a shallow, a receiver crossing the field 2 to 5 yards deep (some teams call that route a drag), under a dig or ‘sit’ route coming from the other side at 10–12 yards: a high-low read of the middle linebacker, and a route that runs away from man defenders. A staple of the Air Raid. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Shell (coverage shell): The picture the safeties show before the snap, above all one-high or two-high. It hints at the coverage to come but can be disguised. Taught in A First Look at Defense.
Shield punt: The family of modern punt formations: two gunners split wide, a line of interior blockers, and a ‘shield’ of blockers a few yards in front of the punter that walls off rushers before they reach the spot of the kick. In the NFL the base version is usually called the spread punt, with two wings a yard behind the line and a personal protector about six yards deep forming the shield; the college version puts three blockers side by side. Taught in Field Goals, Extra Points, and the Punting Game.
Shift: Two or more offensive players changing position or stance at the same time before the snap. After the last shift, all eleven must be set for at least one full second before the ball is snapped. Taught in The Pre-Snap Phase.
Short motion: A motion of only a few yards, usually a receiver tightening his split or tucking in beside or behind a teammate, often set again before the snap. Some offensive playbooks call it rip (right) and liz (left), the same words many defenses use for their strength call. Taught in Motion and Shifts as Weapons.
Short side: See Boundary side.
Shot alert: See Alert.
Shot play: A play built to throw deep, usually 20 or more yards downfield, called in a situation the offense has chosen for it; most are play-action passes with extra blockers and only two or three receivers in the pattern. Taught in Play-Action, Bootlegs, and Screens.
Shotgun: The quarterback standing about five yards behind the center (four to seven, by team) and taking a snap thrown back to him through the air. Taught in Formation Rules and the Language of Alignment.
Shovel pass: A short underhand forward pass, usually flipped by a quarterback moving sideways to a teammate crossing just in front of him behind the line of scrimmage. Because it is a forward pass, a drop is an incompletion, not a fumble. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Side judge: The deep official on the down judge’s side, about 20 yards past the line near the sideline. He watches the receivers on his side for pass interference, illegal contact and holding, and rules on catches and out of bounds near his sideline. Taught in Officiating, Replay, and the Rules of the Ball.
Sideline: One of the two long boundary lines along the sides of the field. The sideline itself is out of bounds. Taught in The Game in Fifteen Minutes.
Sideline camera: The broadcast’s main camera, high on one side of the field near midfield. It follows the ball with a fairly tight shot, which is good for the ball and the faces and poor for the safeties and the receivers away from the ball. Taught in How to Watch a Broadcast Like You Mean It.
Sight adjust: A receiver changing his route after the snap because he sees a blitz, typically cutting a deep route off short so the quarterback, who sees the same blitz, can throw it quickly. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Signing-bonus proration: The cap rule that spreads a signing bonus evenly over the contract’s years, up to five, even though the player is paid the money up front. A $50 million bonus on a five-year deal counts $10 million a year. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Silent count: A snap signal that uses no sound: the quarterback gives a visual cue, the center (who sees it himself, or gets a tap from a guard who does) lifts his head, and the line counts the beats silently. Used when the crowd is too loud to hear the quarterback. Taught in The Pre-Snap Phase.
Sim pressure: See Simulated pressure.
Simulated pressure: A four-man rush built to look like a blitz: one or more players the protection expects to rush drop into coverage, and one or more it expects to cover rush instead, so the defense gets a blitz’s confusion with seven players still in coverage. Taught in Zone Blitzes, Fire Zones, and Simulated Pressure.
Single wing: A direct-snap formation that dominated football from the 1910s into the 1940s: an unbalanced line, a tailback four to five yards deep who took the snap through the air and could run, pass or hand off, a fullback beside him, a blocking back near the line and a wingback just outside the end. The ancestor of the shotgun and the wildcat. Taught in From the Single Wing to the 1970s Scoring Drought (1906–1977).
Single-high: See One-high.
Singleback: Any formation with exactly one running back, lined up directly behind a quarterback who is under center, usually about seven yards deep. The second back of older formations becomes a tight end or a receiver. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Situational call sheet: A call sheet organized by game situation (down and distance, field zone, clock, score) rather than by play, with a short, ranked list of prepared calls in each box, so the play-caller can find the answer for ‘third-and-5’ or ‘inside the 10’ in a second or two. Taught in The Game Plan: A Week Inside an NFL Building.
Skill positions: The offense’s ball-handling positions (quarterback, running back, wide receiver and tight end), as opposed to the linemen. Taught in The Twenty-Two.
Sky rotation: A Cover 3 rotation in which a safety comes down to play the curl-flat area on one side (‘s’ for safety), while the cornerback on that side keeps his deep third. Taught in Cover 3: Sky, Buzz, Cloud, and Seattle’s Match Version.
Skycam: A camera hung from cables above the field that can fly anywhere over it, usually just behind the offense. It shows roughly the quarterback’s view of the defense: the coverage, the safeties and the routes. Taught in How to Watch a Broadcast Like You Mean It.
Slant: A route that takes one to three steps upfield, then cuts sharply inside at roughly 45 degrees into the space between defenders a few yards past the line (the 2 in many route trees). Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Slant (line movement): A called line movement in which defensive linemen step hard across the face of the blocker in front of them at the snap, into the next gap over, gaining only a little ground, usually all in the same direction, while the linebackers shift the other way to fill the gaps the line left. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Slant-flat: A two-receiver quick concept: the outside receiver runs a slant and the inside receiver a flat route underneath it, so the one defender between them can’t cover both. A high-low read. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Slide protection: A pass protection in which the offensive linemen block areas instead of men: each slides one way and takes the gap on that side, whoever rushes through it, while a back or tight end takes the edge rusher the slide leaves behind. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Slot: The area between the outside receiver and the end of the offensive line, and the receiver who lines up there, usually off the line. Taught in Formation Rules and the Language of Alignment.
Slot cornerback: A cornerback who covers the slot receiver, lining up inside between the outside corner and the linemen; the fifth defensive back in a nickel defense. Taught in The Twenty-Two.
Slow screen: The classic screen to a running back: the linemen pass-block for a count or two and let the rushers through, the back pretends to block and slips out behind them, and the quarterback drifts back and throws over the rush to the back, with three linemen in front of him. Taught in Play-Action, Bootlegs, and Screens.
Sluggo: A double move: a slant fake (‘slant and go’), then straight up the field past the defender who bit on the slant. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Smash: A two-receiver concept on one side: the outside receiver runs a short hitch and the inside receiver a corner route over the top of him. A high-low read of the cornerback, built to beat Cover 2, in which the cornerback sits short. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Smoke screen: See Now screen.
Snag: A three-receiver triangle concept: the outside receiver settles at five or six yards just inside his alignment (the snag), the slot runs a corner route behind him and a back or tight end runs to the flat, so two defenders face three receivers at three depths. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Snap: The center’s handing or tossing of the ball back between his legs to the quarterback (or another back). It starts every play from scrimmage. Taught in What a Play Really Is.
Snap count: See Cadence.
Snap share: The share of a team’s offensive plays on which a player is on the field, from the official snap counts. It is the first filter of fantasy usage: a player can’t get the ball on a play he isn’t in for. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Snap-hold-kick: The three-man field-goal and extra-point operation: the long snapper fires the ball about seven or eight yards back, the holder catches it and spots it on its point with the laces turned away, and the kicker strikes it, all in about 1.3 seconds from snap to kick (the ‘operation time’). Taught in Field Goals, Extra Points, and the Punting Game.
Solo: See 3x1 check (solo / stubbie).
Source break: A point in a data series where the supplier or the way of recording changes, so numbers on the two sides are not directly comparable. In nflverse participation data the big one is between 2022 (Next Gen Stats) and 2023 (FTN). Taught in Working with nflverse Data in Python.
Spacing: A quick concept that spreads four or five receivers across the field at about the same depth (five or six yards), each settling in the gap between two zone defenders: a horizontal stretch of the whole underneath coverage. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Special teams coordinator: The assistant in charge of the kicking game: kickoffs, punts, field goals, and the units that return and cover them. Taught in What a Play Really Is.
Speed option: A two-way option with no dive: the quarterback runs straight at the end man on the line of scrimmage with a back trailing him in pitch position, and pitches if the end takes him or keeps if the end takes the pitch man. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Speed out: A quick out route run at full speed with a rounded break toward the sideline, thrown before the receiver breaks, usually against a cornerback playing off and inside. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Speed rush: A pass rush that tries to beat the offensive tackle around the outside, to the corner of the pocket, before he can get in front: a fast get-off, a curved path (the arc), a dip of the shoulder under the tackle’s hands, and a bend back toward the quarterback. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Speed-to-power: A rush that starts as a speed rush to make the tackle retreat fast, then turns straight into him and converts that speed into a bull rush while his weight is still going backward and he cannot anchor. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Spike: A quarterback taking the snap under center and immediately throwing the ball straight into the ground. It is a legal incomplete pass, not intentional grounding, and it stops the clock at the price of a down. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Spill: A run-fit technique in which a defender meets a kick-out or pulling blocker on the blocker’s inside half, often by diving under the block with his outside shoulder (a ‘wrong arm’), to pile up the hole and make the ball bounce outside toward the force player and the pursuit. Taught in Run Fits: Gap Integrity, Force, Spill, and Box Math.
Spin (safety rotation on motion): The safeties rotating in answer to motion: one comes down (usually on the side the motion is heading to, sometimes the other side) and the other moves to the deep middle, so two deep safeties become one. Taught in Motion and Shifts as Weapons.
Spin move: A pass rush counter in which the rusher, with the blocker committed to one side, plants and spins all the way around, back toward the other side, to come free; very effective when it works, and it can carry him out of the play when it doesn’t. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Split (receiver split): How far a receiver lines up from the ball or the formation, usually set by field landmarks such as the numbers and the hash rather than a fixed number of yards. Taught in Formation Rules and the Language of Alignment.
Split backs: See Pro set.
Split end: See X receiver.
Split zone: Inside zone with a tight end or H-back crossing behind the line to kick out the backside end, who would otherwise be left unblocked. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Split-field coverage: Playing a different coverage on each half of the field (for example quarters to the wide side and Cover 2 to the short side), with each half following its own rules for the receivers on its side. Taught in Disguise, Rotation, and Split-Field Coverage.
Split-safety: See Two-high.
Spot (of the ball): Where the officials place the ball for the next play: at the farthest point of its forward progress on the last play, moved in to the nearer hash mark if it ended outside them. Taught in Downs, Distance, and Field Position.
Spot foul: A foul enforced from the spot where it happened rather than from where the ball was snapped. In the NFL the famous one is defensive pass interference, which puts the ball where the foul occurred. Taught in Contact Rules and Penalties as Strategy.
Spot-drop zone: Zone coverage in which each defender drops to a fixed landmark and then reacts to the quarterback’s eyes and the throw, guarding his area rather than any particular receiver. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Spread formation: Any formation that lines its pass-catchers up across the width of the field, toward both sidelines, usually with the quarterback in the shotgun, so the defense has to spread out to cover them. Not the same thing as a ‘spread offense,’ which is a whole philosophy built on such formations. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Spread offense: An offensive philosophy, grown mostly in college football, that lines up in the shotgun with three or four receivers spread across the field to pull defenders out of the box, then attacks the space that leaves with quick passes, option reads or both. A spread formation is the picture; a spread offense is the whole system built on it. Taught in The College Laboratory: Wing-T, Wishbone, Air Raid, Spread Option, and the RPO.
Spread option: A spread offense whose run game is built on option reads from the shotgun or pistol (the zone read and its relatives), so the quarterback’s running threat gives the offense an extra man; popularized by Rich Rodriguez and Urban Meyer in the 2000s. Taught in The College Laboratory: Wing-T, Wishbone, Air Raid, Spread Option, and the RPO.
Spread punt: See Shield punt.
Spy: A defender (usually a linebacker, safety or nickel back) assigned to the quarterback instead of a receiver or a rush lane: he stays at linebacker depth, keeps his eyes on the quarterback, mirrors his movement and tackles him if he runs or scrambles. Taught in Third Down: The Money Down.
Squat corner: See Hard corner.
Squeeze: See Box technique.
Squib kick: A deliberately low kickoff that hits the ground early inside the landing zone and skips or bounces, so it is hard to field cleanly, releases the coverage at once, and is usually aimed away from the most dangerous returner. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Stack: Two receivers lined up one directly behind the other, the front man on the line and the back man a yard or two behind him. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Stack alignment: A linebacker lined up directly behind a defensive lineman, four or five yards deep, using him as a shield. The lineman takes one gap and the linebacker the other, and the offense cannot tell before the snap which will go where. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Stacked box: See Loaded box.
Stacking (a defender): Getting directly in front of a defender who is trailing in coverage, on his line, so he has to go through the receiver to reach the ball. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Stance (two-point / three-point): How a player stands just before the snap. In a two-point stance he is upright, with only his feet on the ground; in a three-point stance one hand is also on the ground (a four-point stance puts both hands down). Taught in How to Watch a Broadcast Like You Mean It.
Stand-up edge: An edge player who lines up at the end of the line of scrimmage standing in a two-point stance instead of with a hand on the ground, so he can rush the passer, set the edge against the run or drop into coverage; in 3-4 defenses he is called an outside linebacker. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Standardised play direction: Rotating the coordinates of every play that went toward the left end zone by 180 degrees, so all plays in a data set move the same way (left to right) and can be compared and stacked. Taught in Tracking Data and the Big Data Bowl.
Stated confidence: The probability you attach to a prediction before the snap, said or written as a number (55%, 70%, 90%) rather than a feeling, so that it can be scored later. A well-judged 70% call comes true about seven times in ten. Taught in Watching Live: The Master Checklist and Anticipation.
Stem: The part of a route between the release and the break. The receiver uses its direction and speed to move the defender where he wants him before he breaks. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Stick: A three-receiver quick concept: one receiver runs to about six yards and settles facing the quarterback (the stick), one runs to the flat, and the outside receiver clears out deep. The quarterback reads the flat defender. Taught in The Quick Game: Slant-Flat, Stick, Snag, Quick Screens, and Beating Press.
Sticks route: A route whose depth is set by the line to gain, usually so the receiver breaks or settles a yard or two past it, so that a catch at the break is a first down without needing any yards after the catch. Taught in Third Down: The Money Down.
Stretch: The widest zone track, aimed outside the tight end toward the sideline, whose first intent is to get the edge; in some playbooks simply another name for outside zone. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Strong I: See Offset I.
Strong safety: The safety who usually lines up on the strong (tight end) side, a little closer to the line, and helps more against the run. Taught in The Twenty-Two.
Strong side: The side of the formation where its strength is: usually the side with the tight end. Taught in Formation Rules and the Language of Alignment.
Stubbie: See 3x1 check (solo / stubbie).
Stunt: A planned pass-rush movement in which two or more rushers exchange gaps after the snap: one goes first to occupy blockers (the penetrator) and the other loops around behind him into the space he left (the looper). Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Substitution freeze: The effect of an offense keeping the same eleven players and lining up fast: because the rules protect the defense’s right to match only when the offense substitutes, the defense cannot safely change its own players and is ‘frozen’ in whatever personnel it had on the field. Taught in In-Game Adjustments, Tempo, and the Sideline Battle.
Substitution matching: The defense changing its players in answer to the offense’s personnel: more defensive backs against more receivers, more linebackers and linemen against more tight ends and backs. NFL rules protect it: when the offense substitutes, the defense must get a chance to respond before the snap. Taught in Personnel: Who’s on the Field Before Anything Else.
Success rate: The share of a team’s or player’s plays with positive EPA: plays that left the offense better off than it was before the snap. Taught in Downs, Distance, and Field Position.
Sugar huddle: A quick huddle a few yards from the ball, broken almost at once, followed by a sprint to the line and a fast snap: the reliability of a huddle without giving the defense time to substitute or set its own call. Taught in In-Game Adjustments, Tempo, and the Sideline Battle.
Surplus value: What a player produces minus what he is paid. For a draft pick it is the on-field value the pick is expected to bring during the rookie contract, minus the rookie wage scale cost of that slot. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Swim move: A pass rush move that clears the blocker’s hands with one hand and then throws the other arm over the top of his shoulder, like a swimming stroke, to get past him. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
Swing route: A running back’s route that bows backward, then out toward the sideline, so he catches the ball on the move behind or at the line of scrimmage. Unlike a screen, nobody is set up to block for him. Taught in Play-Action, Bootlegs, and Screens.
Swinging gate: A trick alignment, used mostly on extra points and two-point tries, in which the snapper stays over the ball and most of the other linemen line up in a group far out to one side. If the defense doesn’t follow, the offense snaps it and attacks the uncovered group; if it does, the offense shifts back into its normal formation. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.

T

T-E stunt: A two-man stunt in which the defensive tackle goes first, driving into the offensive tackle’s inside half to pick him and take over contain, and the end loops around behind him into the inside gap the tackle left. Taught in The Pass Rush: Moves, Stunts, and Why Pressure Beats Sacks.
T-formation: A formation with the quarterback under center and three running backs side by side about four to five yards behind him, the ancestor of almost every modern under-center formation. Its modern form spread through football after 1940. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Tackle (position): One of the two offensive linemen on the outside of the line, next to the guards; usually the tallest, longest-armed linemen, whose main job is blocking pass rushers off the edge. Taught in The Twenty-Two.
Tackle box: The area between the outside edges of where the two offensive tackles lined up, from the line of scrimmage back to the offense’s own end line; in the rulebook, the ‘pocket area’. Inside it, a throwaway must go near an eligible receiver; once the passer, or the ball, has been outside it, a throwaway only has to reach the line of scrimmage. Taught in Officiating, Replay, and the Rules of the Ball.
Tackle over: See Unbalanced line.
Tackle-eligible: See Eligible tackle.
Tag: A word added to a play call that changes one player’s job (for example, one receiver’s route) and leaves the rest of the play alone. Taught in What a Play Really Is.
Tampa 2: A Cover 2 variation in which the middle linebacker, instead of sitting in the short middle, turns and runs down the middle of the field at the snap and carries any receiver who goes up the seam, closing the gap between the two deep safeties. Built by Tony Dungy and Monte Kiffin’s Tampa Bay Buccaneers (1996–2008) and named after their city, from roots in Bud Carson’s 1970s Steelers. Taught in Cover 2 and Tampa 2.
Target share: The share of a team’s targets (passes thrown with an intended receiver) that go to one player, usually counted over the games he played. It measures how much of the passing game the play-caller and quarterback aim at him, independent of how much the team throws. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Technique (alignment number): A number that says exactly where a defensive lineman lines up relative to the offensive linemen: even numbers head-up on a lineman (0 on the center, 2 on a guard, 4 on a tackle), odd numbers on an outside shoulder, and an ‘i’ for an inside shoulder (2i, 4i). Systems differ around the tight end. Taught in The Language of the Run Game: Gaps, Techniques, and Blocks.
Tell: A detail before the snap that leaks what a player or team is about to do, such as a lineman’s stance or a safety’s depth. A clue that shifts the odds, never a guarantee. Taught in How to Watch a Broadcast Like You Mean It.
Tempo: How fast an offense operates between plays: how quickly it gets to the line and snaps the ball after the previous play ends. Offenses vary it on purpose, from a slow, clock-draining pace to a sprint. Taught in In-Game Adjustments, Tempo, and the Sideline Battle.
Tendency: A pattern in what a team does in a given situation, formation or personnel grouping (for example, running on four snaps in five from one look) that an opponent can find on film or in data and play against. Taught in Constraint Theory: How Plays Talk to Each Other.
Tendency breaker: A play called on purpose against a team’s own tendency, such as a pass from a look that usually means run, to punish an opponent who has studied the tendency and to keep the pattern from turning into a giveaway. Taught in Constraint Theory: How Plays Talk to Each Other.
Tendency report: The quality control staff’s written breakdown of what an opponent does in each situation, personnel group and formation (run or pass, which direction, which coverage, how often it blitzes), built from weeks of tagged film and used to build the game plan. Taught in The Game Plan: A Week Inside an NFL Building.
Terminology: See Verbiage.
Texas route: See Angle route.
The numbers (alignment landmark): The painted yard-line numbers, whose tops sit about 14 yards in from each sideline in the NFL. Receivers align by them: ‘on the numbers’, ‘outside the numbers’, ‘inside the numbers’. Taught in Formation Rules and the Language of Alignment.
The sticks: The two poles, joined by a 10-yard chain, that the sideline crew uses to mark where a series began and where the line to gain is. ‘Moving the sticks’ means earning a first down. Since 2025 they are a backup to camera-based measurement. Taught in Downs, Distance, and Field Position.
Third-down package: The personnel and calls a team keeps for third down. On defense: extra defensive backs (often dime), pass-rush specialists, and its pressures, disguises and spies. On offense: its best quick concepts and man-beaters, the protections for the opponent’s pressures, and the receivers and back it trusts most there. Taught in Third Down: The Money Down.
Three-high safety defense: A defense that shows three safeties deep before the snap, usually from a 3-3-5, so that eight players can drop into coverage against the pass or one of the safeties can come down after the snap to fill against the run; made famous by Iowa State in 2017 against the Big 12’s passing offenses. Taught in The College Laboratory: Wing-T, Wishbone, Air Raid, Spread Option, and the RPO.
Throwaway: A pass the quarterback deliberately throws where nobody can catch it (out of bounds, or over a covered receiver’s head) to avoid a sack or an interception: he gives up the down but keeps the yardage. It must be thrown so that it is not intentional grounding. Taught in Quarterback Play: Progressions, the Pocket, and Off-Script Football.
Tight end: A hybrid of lineman and receiver who often lines up right next to a tackle (tight to the line), blocks on running plays and runs routes on passing plays. Taught in The Twenty-Two.
Time to throw: Seconds from the snap to the release of a pass; Next Gen Stats averages it over attempts, with sacks excluded. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Timeout: A stoppage a team calls to stop the clock (and to talk). Each team gets three per half, and two in a regular-season overtime. Taught in The Game in Fifteen Minutes.
Timing route: A route the quarterback throws to a spot at a set moment, as his drop ends and often before the receiver has made his break, so the ball and the receiver arrive together. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Tite front: An odd front with five men on the line: a nose on the center and two defensive linemen in 4i-techniques on the tackles’ inside shoulders, with an edge player outside each tackle. The three interior linemen cover the center and both B gaps, walling off inside runs so the linebackers stay unblocked and the defense can keep two safeties deep. Taught in Odd and Hybrid Fronts: 3-4, Okie, Tite, and Modern Nickel Fronts.
Toss / sweep: An outside run around the end: in a toss, the quarterback pitches the ball to a back already moving wide; in a sweep (handed or pitched), pulling linemen lead the back around the corner. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Total QBR: See QBR.
Touchback: A ball declared dead in or behind a team’s own end zone that the opponent kicked or carried there, with the defending team taking over at a fixed yard line instead of risking a safety. After a punt or a missed field goal from inside the 20, the ball goes to the 20; after a kickoff, see the kickoff chapter. Taught in Field Goals, Extra Points, and the Punting Game.
Touchdown: Six points, scored by carrying the ball into the opponent’s end zone, or by catching or recovering it there. Taught in The Game in Fifteen Minutes.
Tracking data: The recorded position of every player (and usually the ball) many times a second, with speed, acceleration and body angles derived for each moment. In the NFL it comes from chips in the shoulder pads, at 10 frames a second. Taught in Tracking Data and the Big Data Bowl.
Trade (TE trade): The tight end changing sides of the formation before the snap, usually as part of a shift in which a receiver also steps on or off the line. It flips the formation’s strength, so the defense has to re-declare. Taught in Motion and Shifts as Weapons.
Trade deadline: The last day in a season on which NFL teams may trade players: since 2024, the Tuesday after Week 9. After it, rosters can change only through free agents, waivers and practice squads. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Trail technique: A man-coverage position in which the defender runs a step behind and underneath his receiver, on his hip, to take away short and in-breaking throws, trusting a safety to help over the top. Taught in Coverage Fundamentals: Zones, Leverage, and Reading the Shell.
Transition tag: A cheaper cousin of the franchise tag, priced from the top ten salaries at the position: the player is held for one year, other teams may sign him to an offer sheet, and his team gets only the right to match, with no compensation if it doesn’t. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Trap: A run in which the offense leaves a defensive lineman unblocked at the snap, lets him come across the line, and then blocks him from the side with a pulling lineman, so the ball can cut inside him. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Trap coverage: See Palms.
Travel (man defender follows motion): A defender running with a player in motion and staying with him across the formation. The classic sign of man coverage. Taught in Motion and Shifts as Weapons.
Triangle read: A three-receiver read in which the receivers form a triangle around two underneath defenders, one route high and two low (or two high and one low), so the quarterback has a high-low and an inside-outside choice at once. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Triple option: An option with three possible ball carriers and two read keys: the quarterback reads the first defender (the dive key) to give to the diving back or keep, then, if he keeps, reads the next defender (the pitch key) to pitch to a trailing back or keep. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Trips: See 3x1.
Tunnel screen: A wide receiver screen in which the receiver comes back inside, toward the ball, and catches it behind the line between blockers: linemen who have released outward and a teammate blocking the defender outside him, which forms the ‘tunnel’ he runs through. Taught in Play-Action, Bootlegs, and Screens.
Turnover: Losing the ball to the other team without kicking it: an interception, a lost fumble or a turnover on downs. Taught in Downs, Distance, and Field Position.
Turnover luck (fumble-recovery rate): The part of a team’s turnover record that is chance rather than skill, clearest in fumble recoveries: who falls on a loose ball is close to a coin flip, so a team’s recovery rate swings at random from year to year. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Turnover on downs: Failing to reach the line to gain on fourth down. The other team takes over wherever the ball ended up. Taught in Downs, Distance, and Field Position.
Tush push: A quarterback sneak in which two or three teammates line up directly behind the quarterback and shove him forward from behind at the snap; made famous by the Philadelphia Eagles from 2022 and nicknamed the Brotherly Shove. Taught in Red Zone, Goal Line, Two-Point Plays, and Short Yardage (Including the Tush Push).
Two-gap: A style of defensive line play in which a lineman lines up head-up on a blocker, controls him with his hands, reads where the ball is going, and then sheds the block to fill the gap on whichever side the ball comes, so one defender covers two gaps. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Two-high: A coverage shell with two safeties deep, one on each side of the middle of the field, each usually guarding the deep part of his half of the field. Taught in A First Look at Defense.
Two-high counterrevolution: The NFL’s league-wide turn, from about 2019, toward defenses that show two deep safeties before the snap and then either play a two-deep coverage (quarters, Cover 6, Cover 2) or rotate out of that shell at the snap. It answered the play-action and explosive passing offenses of 2017-2020 by taking away the deep ball and the intermediate middle, and it paid for that with lighter boxes against the run. Next Gen Stats measured split-safety coverage (after the snap) on 32.9% of dropbacks in 2018 and 42.0% in 2025. Vic Fangio is the coach most associated with it. Taught in The Modern Era: McVay, Mahomes, Two-High, and the Under-Center Comeback (2017-2025).
Two-minute drill: The hurry-up offense a team runs when it needs to score with little time left in a half, usually the last two minutes: no huddle, plays called in pairs, throws to the sideline so receivers can step out of bounds, and timeouts and spikes used to stop the clock. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Two-minute warning: An automatic timeout in the second and fourth quarters, taken after the last play that started with more than 2:00 on the game clock. Taught in The Game in Fifteen Minutes.
Two-point chart: A lookup table, keyed by the score margin right after a touchdown, telling a coach whether to kick the extra point or go for two; the classic version assumes few scores remain, so it matters most late in a game. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Two-point conversion: The alternative to the extra point: one play from the 2-yard line, worth two points if the ball is run or caught into the end zone. Taught in The Game in Fifteen Minutes.
Two-way concept: A pass concept with an answer built in for both man and zone coverage, either because the same routes win against both (crossers that rub against man and settle in holes against zone) or because a receiver changes his route after the snap according to the coverage, so the play is not a bad call whatever the defense plays. Taught in What Beats What: Reading Coverage and Pass Concepts Versus Coverages.
Two-way go: A receiver with enough room on both sides of the defender covering him that he can break either inside or outside, so the defender has to guess. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.

U

UFA: See Unrestricted free agent.
Umbrella defense: Steve Owen’s New York Giants defense of 1950: a 6-1-4 alignment (six linemen, one linebacker, four defensive backs) whose two ends could drop into pass coverage after the snap, so against a pass it became a 4-1-6. Built to stop Paul Brown’s Cleveland Browns; one of the ancestors of the 4-3. Taught in From the Single Wing to the 1970s Scoring Drought (1906–1977).
Umpire: The official responsible for the interior line: holding, false starts and illegal hands among the center, guards and the defenders across from them. Since 2010 he stands in the offensive backfield, opposite the referee; he also spots the ball after most plays and checks equipment. Taught in Officiating, Replay, and the Rules of the Ball.
Unbalanced line: An offensive line with more linemen on one side of the center than the other, usually by moving a tackle to line up beside the other tackle (‘tackle over’), so one side has an extra blocker. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Unblocked rusher: The rusher the protection leaves untouched on a particular snap. Blitz design is a fight over who he will be: the offense’s rules try to make him the man with the longest path to the quarterback, the defense’s design tries to make him the man with the shortest. Taught in Blitzing: Numbers, Overloads, A-Gap Mugs, and Cover 0.
Under center: The quarterback standing directly behind the center with his hands under him, taking the snap hand to hand. Taught in Formation Rules and the Language of Alignment.
Under-center revival: The reversal, from 2024 to 2025, of a six-season slide in how often NFL quarterbacks took the snap directly behind the center: from about 41% of plays in 2017 down to about 28% in 2023, then back to about 34% in 2025. It was led by a handful of outside-zone, play-action, heavy-personnel offenses (the 2025 Rams and Seahawks were under center on more than half their plays) that wanted a run and a pass to look identical for as long as possible against two-high defenses. Taught in The Modern Era: McVay, Mahomes, Two-High, and the Under-Center Comeback (2017-2025).
Unnecessary roughness: The catch-all personal foul for needless or dangerous contact: late hits after the whistle, hits on a player out of bounds, forcible hits on a defenseless player, and the like. Fifteen yards, plus an automatic first down when the defense commits it. Taught in Contact Rules and Penalties as Strategy.
Unrestricted free agent: A player whose contract has expired and who has at least four accrued seasons (seasons with six or more games on full pay status). He may sign with any team, and his old team gets nothing back except, sometimes, a compensatory pick. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Use of the helmet (2018 rule): The NFL rule, adopted in 2018, that makes it a foul for any player anywhere on the field to lower his head to initiate and make contact with his helmet against an opponent. Fifteen yards, and the player may be ejected. Taught in Contact Rules and Penalties as Strategy.

V

Value over replacement: In fantasy drafting, a player’s projected points minus those of the replacement-level player at his position (roughly the worst starter in the league, or the best player available for free). It lets you compare players across positions and is the core of value-based drafting. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
Veer: An option blocking-and-read rule from Bill Yeoman’s 1960s Houston teams: the play-side tackle releases inside, leaving the first defender outside him unblocked as the dive key, and the quarterback gives to the diving back or keeps. Add a pitch man and the veer becomes the triple option. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Verbiage: A team’s play-calling language: the words it uses for formations, motions, protections and plays. Taught in What a Play Really Is.
Vertical set: A tackle’s pass set straight back for depth, giving ground fast so a speed rusher has to run a longer arc around him. Taught in Pass Protection: Slides, Man Schemes, and Who Blocks the Extra Guy.
Vertical stretch: See High-low read.
Vice: A punt-return player assigned to block a gunner at the line and run with him, usually two to a gunner, to slow the punt team’s fastest coverage players. Coaches often spell it ‘vise’ and, strictly, use it for the two-man bracket, calling a lone blocker on a gunner a ‘jammer’. Taught in Field Goals, Extra Points, and the Punting Game.
Victory formation: The formation a leading team uses to end a half or game by kneeling: the quarterback under center, the line in tight, two backs just behind him to protect the ball and one deep player as a last line of defense against a fumble. The quarterback takes the snap and drops to one knee, and the clock keeps running. Taught in The Clock, the Two-Minute Drill, and Fourth Down.
Virtual measurement: The NFL’s camera-based first-down measurement, used since 2025: a Sony Hawk-Eye system of six 8K cameras in every stadium measures from the officials’ spot of the ball to the line to gain, in place of the chain crew walking onto the field. The officials still spot the ball by eye, and the chains stay on the sideline as a backup. Taught in Officiating, Replay, and the Rules of the Ball.
Void years: Fake final years added to a contract that will cancel automatically before they are played. They exist only to spread a signing bonus over more years, which lowers today’s cap hits; when the years void, the bonus not yet counted becomes dead money. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.

W

Waggle: The Wing-T’s play-action bootleg: the quarterback fakes a run one way (classically the buck sweep) and rolls out the other way behind both guards, who pull to that side to protect him, with receivers at short, medium and deep levels on that side, so he can run or throw. The ancestor of the NFL bootleg. Taught in Perimeter Runs and Misdirection: Jet Sweeps, Reverses, and the Wing-T’s Children.
Waivers: The system for releasing a player who has fewer than four accrued seasons (and, after the trade deadline, anyone): for about a day, every other team may claim him and take over his contract, with priority to the team with the worst record. Taught in Building a Roster: Positional Value, the Cap, Free Agency, and the Draft.
Walk-out: A linebacker moving out of the box before the snap to line up over or near a slot receiver, usually at an apex, so that he can cover the receiver. It takes a defender out of the box and puts him in conflict between the run and the pass. Taught in Linebackers: Keys, Flow, Tackling, and the Hardest Job on the Field.
Wall return: See Return wall.
WCO: See West Coast offense.
Weak I: See Offset I.
Weak side: The side of the formation away from its strength. Taught in Formation Rules and the Language of Alignment.
Wedge: On kickoffs before 2018, a group of blockers who formed up shoulder to shoulder in front of the returner and ran into the coverage together; limited to two players in 2009 and banned in 2018. Taught in Kickoffs, Returns, and the Dynamic Kickoff.
Weighted opportunity rating: See WOPR.
West Coast offense: The family of offenses descended from Bill Walsh’s 1979–1988 San Francisco 49ers: timed short and intermediate passing that stretches the defense sideways, and long play calls that spell out the formation, the protection and many receivers’ routes one by one. Taught in Offensive Systems and Play-Calling Languages.
Wham: A trap block thrown by a tight end or H-back instead of a guard: the line leaves a defensive tackle unblocked, the lineman who would have blocked him releases to a linebacker, and the tight end or H-back comes across and hits the tackle from the side. Taught in Gap Schemes: Power, Counter, Duo, Trap, Wham, Iso, and the Draw.
Wheel: A route that starts out toward the flat and then turns up the sideline, usually run by a running back or a slot receiver. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Whip: A short route in which a slot receiver runs at the middle as if on an in-cut, plants, and snaps back toward the sideline. Built to beat a defender who jumps the first move. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
Wide receiver: A pass-catcher who lines up away from the linemen, near the sideline (split out wide) or in between (the slot). His main job is running routes and catching passes. Taught in The Twenty-Two.
Wide side: See Field side.
Wide zone: See Outside zone.
Wide-9: An alignment for a defensive end far outside the offensive tackle: one to two or more yards outside the tight end, or, with no tight end, just as far beyond where one would stand (roughly three to four yards outside the tackle), usually in a sprinter’s stance (a three-point stance with the weight forward and tilted toward the quarterback). A 9 sits on the tight end’s outside shoulder; the wide-9 is a clear step or two beyond. It gives the end the widest angle to rush the passer at the cost of a wider running lane inside him. Taught in Defensive Line Play: Techniques, One-Gap and Two-Gap.
Wildcat: A formation in which the ball is snapped directly to a running back (or another non-quarterback) standing in the shotgun, while the quarterback lines up as a receiver or leaves the field. Popularized in the NFL by the 2008 Miami Dolphins. Taught in Spread Formations: 2x2, Trips, Bunch, Empty, and the Condensed Revolution.
Will linebacker: The weak-side linebacker (W), lined up on the side of the formation away from the tight end; usually the fastest linebacker, who chases plays from behind. Taught in The Twenty-Two.
Win probability: A model’s estimate of the chance that a team wins the game from the current situation: the score, the time left, field position, down and distance, timeouts and, in some versions, the pregame point spread. It is built from how similar situations turned out in past games. Taught in Win Probability and Decision Analysis: Fourth Downs, Two-Pointers, Timeouts.
Win probability added: See WPA.
Wing: A player lined up a yard off the line just outside the end man, usually a tight end or H-back. Being off the line makes him a back: eligible, and free to go in motion. Taught in Formation Rules and the Language of Alignment.
Wing-T: A formation and system that mixes the T with the single wing: a fullback behind the quarterback, a halfback beside him, and a wingback just outside and behind the tight end. Built for misdirection, so that every play starts with the same backfield action. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
Wishbone: A three-back option formation: the fullback close behind the quarterback and two halfbacks deeper and wider, one on each side, so the backfield looks like an upside-down Y. Built for the triple option; invented at Texas in 1968. Taught in Classic Formations: I, Power I, Pro Set, Singleback, and Their Ancestors.
WOPR: Weighted opportunity rating: 1.5 times a receiver’s target share plus 0.7 times his air-yards share, Josh Hermsmeyer’s one-number summary of how much passing-game opportunity a receiver gets. About 0.7 or higher is a team’s clear number-one target; 0.4 to 0.5 is a typical second receiver. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.
WP: See Win probability.
WPA: Win probability added: a team’s win probability just after a play minus its win probability just before it. Summed over a game, a team’s WPA runs from its starting win probability to 100% if it wins (or 0% if it loses). Taught in Win Probability and Decision Analysis: Fourth Downs, Two-Pointers, Timeouts.
Wrap: See Log block.
Wristband: A small play card worn on the wrist, with plays listed by number, so a short code can stand in for a long call. Taught in What a Play Really Is.

X

X receiver: The wide receiver who lines up on the line of scrimmage, usually alone on the side away from the tight end. He is on the line so that the formation has an end on that side. Taught in Formation Rules and the Language of Alignment.
xpass: Expected pass rate: a model’s probability that an average NFL offense would call a pass (a dropback, so sacks and scrambles count) in a given situation, from the down, distance, field position, score and clock. Averaged over a team’s snaps, it is the pass rate those situations alone would predict. Taught in Tendencies: PROE, Personnel, Motion, and Coverage from Charting Data.

Y

Y receiver: The playbook letter for the main tight end in most NFL offenses. (Some spread systems use Y for a slot receiver.) Taught in Formation Rules and the Language of Alignment.
Y-cross: An Air Raid concept in which a receiver from one side (traditionally the Y) runs a deep crossing route to the far side at 15–18 yards, under a go route that clears the cornerback and over a flat route: a three-level stretch built from across the field. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
YAC: Yards after catch: the yards a receiver gains after he catches the ball, from the spot of the catch to the end of the play. Taught in Passing Game Fundamentals: Routes, Timing, and Reads.
YAC over expected: Yards after the catch minus the yards after the catch a model expects, given where and how the ball was caught (air yards, field position, the receiver’s spot on the field and, in tracking-based versions, his speed and the defenders around him). Reported per catch; positive means receivers gained more after the catch than the situation predicted. Taught in Case Study: The Shanahan Tree.
YACOE: See YAC over expected.
Yankee: A two-receiver deep shot, usually off play-action with max protection: a post from one side and a deep over route (a crosser at about 18–22 yards) from the other, a high-low read of the single deep safety. Taught in Dropback Concepts: Smash, Flood, Mesh, Levels, Dagger, and Four Verticals.
Yard line: Any line across the field parallel to the goal lines, named by its distance from the nearer goal line (‘the 35’). Lines are painted every 5 yards, with a short tick at every yard. Taught in The Game in Fifteen Minutes.
yardline_100: The play-by-play column for field position: the distance in yards from the ball to the opponent’s goal line. 75 is your own 25, 50 is midfield and 1 is the opponent’s 1, whichever end of the field the team is attacking. Taught in Working with nflverse Data in Python.
Yards after catch: See YAC.
Yards per route run: See YPRR.
Year-over-year stability: How well a statistic in one season predicts the same statistic for the same team or player the next season, usually measured as a correlation; high stability points to skill, low stability to noise or changed circumstances. Taught in Expected Points, EPA, and Success Rate: The Model, the Noise, and the Broadcast Metrics.
Yo-yo: See Return motion.
Yo-yo motion: See Return motion.
YPRR: Yards per route run: a player’s receiving yards divided by the number of pass routes he ran. It rewards both earning targets and doing something with them, and it uses the right denominator, the chances he had to get open. About 1.5 is typical for a regular NFL wide receiver; 2.5 or more is elite. Taught in Scheme and Fantasy: Reading Usage, Not Box Scores.

Z

Z receiver: The wide receiver who lines up a yard off the line, usually on the tight end’s side, which keeps the tight end eligible and leaves Z free to go in motion. Taught in Formation Rules and the Language of Alignment.
Zone blitz: A pressure that sends a defender the offense does not expect to rush (a linebacker or defensive back) and drops one it does expect to rush (usually a defensive lineman) into a short zone, so the defense pressures the quarterback while still playing zone coverage behind the rush. Taught in Zone Blitzes, Fire Zones, and Simulated Pressure.
Zone blocking: A blocking scheme in which every lineman steps the same direction and blocks whoever enters his area, rather than a defender named before the snap. Taught in Zone Running: Inside Zone, Outside Zone, Split Zone, and the Cutback.
Zone coverage: Pass coverage in which each defender is assigned an area of the field and guards whichever receiver comes into it, usually watching the quarterback. Taught in A First Look at Defense.
Zone read: An option run in which the line blocks inside zone and leaves the backside end unblocked; the quarterback reads that end at the mesh and gives to the back if the end stays wide, or keeps and runs outside him if he crashes down on the back. Broadcasters usually call it the read option. Taught in Option Football: Reading Defenders Instead of Blocking Them.
Zoom motion: Motion all the way across the formation that ends with the player set on the other side (in some playbooks it is the Z receiver’s motion, hence the Z in the name), changing the formation, typically from 2x2 into 3x1. Taught in Motion and Shifts as Weapons.