AUDIBLE: An audible is a play called by the quarterback at the line of scrimmage which changes the play that was previously called in the huddle; a change of plans in game play, just before the ball goes into play. Also called an automatic.

AUTOMATIC: See audible, above.

BALANCED LINE: A formation with an equal number of linemen on either side of the center.

BIRDCAGE: The facemask donned by linemen which has extra vertical and horizontal bars.

BLIND SIDE: The side opposite the side the player is looking towards.

BLITZ: An all-out run by linebackers and defensive backs, charging through the offensive line in an effort to sack the quarterback before he can hand off the ball, or pass it. Also called red dogging.

BOOTLEG: The quarterback fakes a hand-off to backs going one way while goes the other way to run or pass.

BLOCK: To contact your opponent, with any part of the body. There are various types of blocks, such as the basic block (which involves chest to chest contact), the shoulder block (which, obviously, involves using one’s shoulder to contact), the scramble or reach block (designed to tangle up an oncoming opponent who is playing outside of your position), and pass blocking (delaying the oncoming defensive line to allow your quarterback to act).

BUTTONHOOK: A pass route in which the receiver heads straight downfield, then abruptly turns back toward the line of scrimmage.

CANADIAN FOOTBALL: Similar to American football,but with some differences, including different field size and scoring. For more information, see our guide to the rules of football.

CANADIAN FOOTBALL LEAGUE(CFL):Canada’s equivalent of the NFL; the association of Canadian professional football teams from various cities in that nation.

CENTER: An offensive line position at the center of the line of scrimmage. The center snaps the ball to the quarterback or punter.

CHAIN CREW: Three assistants to the officials whose job it is to handle the first down measuring chain and the down box.

CHEAP SHOT: A deliberate foul or other violent act against an unsuspecting player.

CHECK OFF: Calling an audible.

CLIPPING: Blocking an opponent from behind, typically at leg level. Clipping is a foul, with a 15-yard penalty.

CLOTHESLINE: A foul. To clothesline is to strike another player across the face with one’s extended arm.

COACH: The trainer of the team who also formulates offensive and defensive strategy. In professional football there is a head coach assisted by several other coaches specializing in certain areas of training, such as offense, defense, strength training, etc.

COFFIN CORNER: One of the four corners of the field. A punter often tries to kick the ball out of bounds near a coffin corner to stop the other team from returning the ball, and make them put the ball back into play close to their own goal-line.

COIN TOSS: Before the start of the game, the quarterback of the visiting team calls heads or tails of a coin flipped by the referee. The winning team kicks off; the loser chooses which goal to defend.

COMPLETION: A legally caught pass.

CONTACT SPORT: Any sport involving physical contact between players. Football is a contact sport, as are hockey, boxing, and soccer.

CONVERSION: See Point After Touchdown.

CORNERBACK: A defensive backfield player, almost as deep into the backfield as the safety. There are two cornerbacks. Their job is to tackle runners and intercept passes.

COVER: To defend a position or location on the field.

CRACKBACK: A foul. Blocking by an offensive player who goes downfield then turns back to the middle to block a player from the side.

CURL/CURL IN: A maneuver where the receiver runs downfield before turning back to run towards the line of scrimmage.

CUT: To suddenly change direction to lose a pursuing player. Also, to drop a prospective player from the team roster.

DEAD BALL: A ball that is no longer in play, that is, a ball that is not held by a player or loose from a kick, fumble, or pass.

DEFENSE: The team defending their goal line. The defense does not have the ball; rather, they attempt to keep the offense from passing or running the ball over their (the defense’s) goal line.

DEFENSIVE BACKFIELD: The area or players behind the defensive linemen. The defensive backfield is the last line of defense against the offense. There are two safeties, two cornerbacks, and three or four linebackers in the defensive backfield.

DEFENSIVE LINEMEN: The players whose job it is to rush the quarterback in an effort to sack him, or, if another player has the ball, to block him and prevent the opposing team from gaining yardage.

DELAY OF GAME: A delay caused by a team using or requesting excessive time-outs, given a 5 yard penalty.

DOWN: An offensive play, starting with a center snap and ending when the ball is dead. The offense gets four downs to gain ten yards. If they gain that before using all four downs, they get a first down and another four downs to gain another ten yards. Each time they gain ten yards, the team is at their first down again, needing another ten yards(first and ten) within the next four downs, or plays.

DOWN AND IN: A maneuver where the receiver runs straight downfield, then suddenly cuts toward the middle of the field.

DOWN AND OUT: The opposite of the above maneuver. In a down and out, the receiver runs downfield then turns out, toward the sideline.

DOWN BOX (DOWN INDICATOR): A seven-foot metal rod, on the end of which are four cards (numbered 1 to 4), used to keep track of the number of the down being played.

DRAFT: The selection of new players into the pro ranks. Teams doing poorly are allowed to choose before those doing well, from among the various top college players.

DRAW PLAY: A fake pass which ends with one of the backs carrying the ball after the defensive linemen are “drawn” in on the pass rush

ELIGIBLE: An offensive player who is able (by the rules) to catch a forward pass; eligible to receive the pass.

ENCROACH: Contacting an opposing player before the snap. Encroaching is illegal, with a five-yard penalty.

END: An offensive lineman on the very end of the line of scrimmage (there are two, one on each end of the line). The ends block defensive linemen to open up holes for the runner, and guard the quarterback. On professional teams, the end on the right side is referred to as a ‘tight’ end, as he lines up close to the tackle. The end on the left side is out farther to go out for passes, and is called a wide receiver.

END LINE: The very end of the field, in either direction. There are two end lines (one at each end of the field).

END ZONE: The area between the goal lines and the end lines; the last ten yards at either end of the field.

EXTRA POINTS: After scoring a touchdown, a team can earn one more point by making a successful place-kick.

FACE MASK: See fouls. Also, the mask itself, worn by the players.

FAIR CATCH: When there is a punt, and a receiver is going to catch the ball and signals that he will not advance after catching it (by raising his hand just before the catch), this is a fair catch. Also, players may not tackle the receiver making the fair catch.

FIELD GOAL: When a place-kick goes through the goalpost (over the crossbar and between the upright bars), three points are earned as a field goal.

FIELD POSITION: The ball’s location on the field.

FIRST AND TEN: See down.

FLAG FOOTBALL: Similar to most other forms of football, but with typically six to nine players, with tackling not permitted. Instead, a flag carried on each side of the player’s belt must be plucked to constitute a tackle.

FLANKER: An offensive player on the right or left side of the formation. A flanker usually plays as a receiver and is split out wider than a wingback.

FLAT:The field on either side of the formation.

FLOOD: An attempt to swamp the opposition or an area of the field with sheer numbers of players.

FORMATION: The arrangement of the players at the beginning of each play. There are several formations. Some of the most common are the punt formation, I formation, T formation, and wishbone formation. These are generally named for the shape of the formation. For instance, an I formation involves two running backs in a line (I-shaped) behind the quarterback, and was invented by college coach Tom Nugent in the 1950s. The wishbone formation has the two half-backs on each side of the full-back set back a few yards as opposed to the T formation in which all three backs are in a line parallel to the line of scrimmage.

FORWARD PASS: Throwing of the ball “forward”, or in the direction of advancement (towards the opponents’ goal).

FOUL: A breaking of the rules. Common fouls are holding (grasping an opponent, unless the opponent has the ball), personal fouls (tripping an opponent or striking an opponent with one’s hand, knee, or head), interference (a defensive player contacting a receiver to stop the completion of a pass or kick by contacting the player before he has the ball), clipping (pushing an opponent in the back), and face mask (grabbing an opponent’s face mask).

FREE AGENT: A professional athlete who is not constrained to deal with one team. Rather, a free agent may sign with any team he or she chooses.

FREE SAFETY: One of the two defensive backs deepest in the field who isn’t assigned a particular area or player to cover and is thus “free”‘ to follow the play anywhere it goes and generally must be a solid pass defender. Also, see Strong Safety.

FREEZE: Holding onto the ball for along time without scoring or attempting to score, to freeze the ball.

FRONT FOUR: The players defensive front line; made up of two ends and two tackles.

FULLBACK: A member of the offense, whose job it is to block for the halfback and quarterback, but he also runs the ball, and receives passes. The name derives from the fact that in an I formation the Fullback is the furthest back, or a full way back. See quarterback and halfback to further clarify.

FUMBLE: A ball that is dropped while in play.

GAME BALL: The ball given to a winning team’s player or coach considered to have most contribution to their win (supposed to be the ball or a ball the game was played with).

GOAL LINE: The line over which the ball must pass to score a touchdown. There are two, one at each end of the field, ten yards from the ends of the field.

GOAL-LINE STAND: Making a stand against the opposition at or near one’s goal-line in a very tough defensive effort.

GRIDIRON: A football field.

GUARD: An offensive lineman. There are two guards, one on either side of the center, whose job it is to guard the quarterback.

HAIL MARY: The quarterback throwing the ball up in the air without really targeting any particular receiver, hoping someone on his side catches it. Typically done when the quarterback’s about to get sacked!

HANG TIME: The time a punt remains in the air.

HALFBACK: Also refered to as Tailback or Runningback. A member of the offense, whose job it is to run the ball, receive passes, and block for a teammate running the ball. The name derives from the fact that in an I formation the Halfback is half way between the Quarterback and the Fullback, or half the way back. See Quarterback and Fullback to further clarify.

HAND OFF: Quite literally what it says: to hand the ball off to a teammate.

HASH MARKS: These marks divide the field into thirds. Whenever the ball becomes dead on or outside one of these marks, it is placed on its respective hash mark.

HITCH AND GO: A maneuver where a runner goes downfield to catch a pass, fakes a quick turn (as if to catch), then continues downfield for a deeper pass.

HOLDER: The player who holds the ball during a place kick.

HOLDING: Keeping another player from advancing by literally holding him back with one’s hand(s). Usually illegal.

HOTDOG: A player who uses theatrics and “hams it up” for the camera. Sound like anyone in the NFL?

HUDDLE: The action of the players grouping together to plan the next play(s). As a noun, the group itself.