Gridiron football

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Diagram of an American football field. Numbers on the field indicate the yards to the nearest end zone. AmFBfield.svg
Diagram of an American football field. Numbers on the field indicate the yards to the nearest end zone.
Diagram of a Canadian football field, wider and longer than the American field. Terrain football canadien2.png
Diagram of a Canadian football field, wider and longer than the American field.

Gridiron football ( /ˈɡrɪdaɪərn/ GRID-iren), [1] also known as North American football, [2] or in North America as simply football, is a family of football team sports primarily played in the United States and Canada. American football, which uses 11 players, is the form played in the United States and the best known form of gridiron football worldwide, while Canadian football, which uses 12 players, predominates in Canada. Other derivative varieties include arena football, flag football and amateur games such as touch and street football. Football is played at professional, collegiate, high school, semi-professional, and amateur levels.


These sports originated in the 19th century out of older games related to modern rugby football, more specifically rugby union football. Early on, American and Canadian football developed alongside (but independently from) each other; the root of the game known as "football" today originates with an 1874 game between Harvard and McGill Universities, following which the American school adopted the Canadian school's more rugby-like rules. [3]

Over time, Canadian teams adopted features of the American variant of the game and vice versa. Both varieties are distinguished from other football sports by their use of hard plastic helmets and shoulder pads, the forward pass, the system of downs, a number of unique rules and positions, measurement in customary units of yards (even in Canada, which largely metricated in the 1970s), and a distinctive brown leather ball in the shape of a prolate spheroid with pointed ends.

The international governing body for the sport is the International Federation of American Football (IFAF); although the organization plays all of its international competitions under American rules, it uses a definition of the game that is broad enough that it includes Canadian football under its umbrella, and Football Canada (the governing body for Canadian football) is an IFAF member.


A 1904 diagram of an American football field. In this period, lines were painted along the length of the field as well as the width, making a checkerboard pattern. Football Diagram 1904.jpg
A 1904 diagram of an American football field. In this period, lines were painted along the length of the field as well as the width, making a checkerboard pattern.

The sport is typically known as simply "football" in the countries where it originated, regardless of the specific variety. [4] Various sources use the term "North American football" when discussing the American and Canadian games together, but this term is quite rare. [5] [6] [7] [8]

The two sports are also sometimes known as "gridiron football". [1] The name originated with the sport's once-characteristic playing field: the original American football and Canadian football fields were marked by a series of parallel lines along both the width and length of the field, which produced a checkerboard pattern resembling a cross-hatched cooking gridiron. [9] [10] [11] The ball would be snapped in the grid in which it was downed on the previous play. By 1920, the grid system was abandoned in favor of the system of yard lines and hash marks used today.

The International Federation of American Football (IFAF), uses "American football" inclusive of Canadian football and other varieties. [12]

In Australia, American football is often referred to as "gridiron" or (in more formal contexts) "American football", as "football" usually refers to Australian rules football, rugby league or rugby union, similar to how association football is usually called "soccer" in Australian English. The governing body for American football in Australia is Gridiron Australia.

Similarly, in the UK American football is known as American football, as "football" is used to refer to soccer.


The sport developed from informal games played in North America during the 19th century. Early games had a variety of local rules and were generally similar to modern rugby union and soccer. The earliest recorded instance of gridiron football occurred at University of Toronto's University College in November 1861. [3]

Later in the 1860s, teams from universities were playing each other, leading to more standardized rules and the creation of college football. While several American schools adopted rules based on the soccer rules of the English Football Association, Harvard University held to its traditional "carrying game". Meanwhile, McGill University in Montreal used rules based on rugby union. In 1874, Harvard and McGill organized two games using each other's rules. Harvard took a liking to McGill's rugby-style rules and adopted them. [3] [13] In turn, they were used when Harvard and Yale University played their first intercollegiate sports game in 1875, and after which the rugby-style Canadian game was adopted by Yale players and spectators from Yale and Princeton University. [13] This version of the game was subsequently played with several other U.S. colleges over the next several years. [3]

American football teams and organizations subsequently adopted new rules which distinguished the game from rugby. [14] Many of these early innovations were the work of Walter Camp, including the sport's line of scrimmage and the system of downs. [15] Another consequential change was the adoption of the forward pass in 1906, which allowed the quarterback to throw the ball forward over the line of scrimmage to a receiver. [16] Canadian football remained akin to rugby for decades, though a progressive faction of players, chiefly based in the western provinces, demanded changes to the game based on the innovations in American football. Over the years, the sport adopted more Americanized rules, though it retained some of its historical features, including a 110-yard (100 m) field, 12-player teams, and three downs instead of four. [17] Around the same time Camp devised the rules for American football, the Canadian game would develop in the same way (but separately) from the American game; the Burnside rules were instrumental in establishing many of the rules for the modern game. [18]


Commonwealth Stadium in Edmonton, a Canadian Football League field originally built for the 1978 Commonwealth Games Commonwealth Stadium, Edmonton, August 2005.jpg
Commonwealth Stadium in Edmonton, a Canadian Football League field originally built for the 1978 Commonwealth Games

Professional leagues

Professional gridiron football leagues
US$ (bn)
attendance (2023)
National Football League United States American football 192032$14.069,528$2,700,000
Canadian Football League Canada Canadian football 19589$0.222,505$89,000
United Football League United States American football 2024814,433$50,000
Indoor Football League United States Indoor football 200816$3,500
Arena Football League United States Arena football 1986 (2024)16
American Indoor Football United States Indoor football 2005 (2023)7
National Arena League United States Indoor football 20168$2,450
Fan Controlled Football United States Indoor football 20218$3,200
Liga de Fútbol Americano Profesional Mexico American football 201682,000$600
X-League (X1/X2/X3) Japan American football 197118/18/17$55,000
European League of Football Europe American football 2021173,200$6,300

The best NFL players are among the highest paid athletes in the world. [19] [20]

Collegiate leagues

NCAA United States American football 19064 [lower-alpha 1] 664No27,142(Div. I) [21]
Flag football 202515No
NAIA United States American football 1940195No
Flag football 2021123No
NJCAA United States American football 1938250No
CCCAA United States American football 1929167No
U Sports Canada Canadian football 1961127No3,370 [22]
ONEFA Mexico American football 1978122No
CONADEIP Mexico American football 2010112No
JAFA Japan American football 19341–5220Yes
KAFA South Korea American football 1945139No
BUAFL United Kingdom American football 2007383Yes
CSFL United States Sprint football 194019No
MSFL United States Sprint football 202218No
NCFA United States American football 1940127No
  1. While the NCAA is formally split into three divisions, the top tier, Division I, is itself split for football only into the Football Bowl Subdivision and the Football Championship Subdivision.

Comparison of codes

Line of
to gain
Forward motion
before snap?
Goal posts
American Fall
100105313117410NoAt back of end zones
1812 (NFL and College) to 2313 (High School) ft. wide
Canadian Summer
1102065127310YesOn goal lines
1812 ft. wide
Indoor Spring508281384410YesAt back of end zones, 9 to 10 ft. wide
Rebound nets on sides optional
6-man Fall80104063415NoAt back of end zones
2313 wide

Play of the game

The football used in North American football has a distinct pointed shape, with a brown color and prominent laces to aid in throwing. American Football 1.svg
The football used in North American football has a distinct pointed shape, with a brown color and prominent laces to aid in throwing.

This is a minimal description of the game in general, with elements common to all or almost all variants of the game. For more specific rules, see each code's individual articles.

Prior to the start of a game, a coin toss determines which team will decide if they want to kick off the ball to their opponent, or receive the ball from their opponent. Each team lines up on opposite halves of the field, with a minimum ten yards of space between them for the kickoff. The team receiving the ball can make a fair catch (which stops the play immediately), catch the ball and run it back until the ball carrier is tackled, or, if the ball is kicked out of bounds, let the ball go dead on its own (the last case usually happens when the ball is kicked all the way into or through the opponent's end zone, resulting in a touchback and the ball being brought several yards out of the end zone to begin play). A kicking team can, under special circumstances, attempt to recover its own kick, but the rules of the game make it very difficult to do so reliably, and so this tactic is usually only used as a surprise or desperation maneuver.

At this point, play from scrimmage begins. The team in possession of the ball is on offense and the opponent is on defense. The offense is given a set amount of time (up to forty seconds, depending on the governing body), during which the teams can set up a play in a huddle and freely substitute players to set into a formation, in which the offense must remain perfectly still for at least one second (the formation requirement does not apply to Canadian football). At least half of the players (seven in standard American and Canadian football, four in standard indoor ball) on the offense must line up on the line of scrimmage in this formation, including the snapper, who handles the ball before play commences; the rest can (and almost always do) line up behind the line. Neither the offense nor the defense can cross the line of scrimmage before the play commences. Once the formation is set, the snapper snaps the ball to one of the players behind him. (A snapper must snap the ball within 20 to 25 seconds of the official setting the ball back into position after the previous play, and a play clock is kept to enforce the measure.) Once the ball is snapped, the play has commenced, and the offense's goal is to continue advancing the ball toward their opponent's end zone. This can be done either by running with the ball or by a rule unique to football known as the forward pass . In a forward pass, a player from behind the line of scrimmage throws the ball to an eligible receiver (another back or one player on each end of the line), who must catch the ball before it touches the ground. The play stops when a player with the ball touches any part of his body other than hand or foot to the ground, runs out of the boundaries of the field, is obstructed from making further forward progress, or a forward pass hits the ground without being caught (in the last case, the ball returns to the spot it was snapped). To stop play, players on defense are allowed to tackle the ball carrier at any time the ball is in play, provided they do not grab the face mask of the helmet or make helmet-to-helmet contact when doing so. At any time, the player with the ball can attempt a backward, or lateral, pass to any other player in order to keep the ball in play; this is generally rare. Any player on defense can, at any time, attempt to intercept a forward pass in flight, at which point the team gains possession; they can also gain possession by recovering a fumble or stripping the ball away from the ball carrier (a "forced fumble"). A typical play can last between five and twenty seconds.

If any illegal action happens during the play, then the results of the previous play are erased and a penalty is assessed, forcing the offending team to surrender between five and fifteen yards of field to the opponent. Whether this yardage is measured from the original spot of the ball before the play, the spot of the illegal action, or the end of the play depends on the individual foul. The most common penalties include false start (when an offensive player jumps to begin the play before the ball is snapped, a five-yard penalty), holding (the grabbing of a player other than the ball carrier to obstruct their progress; a ten-yard penalty against offensive players and a five-yard penalty against defensive ones), and pass interference (when either a receiver or the defending player pushes or blocks the other to prevent them from catching the pass). A team on offense cannot score points as the direct result of a penalty; a defensive foul committed in the team's own end zone, if the penalty is assessed from the spot of the foul, places the ball at the one-yard line. In contrast, a defensive team can score points as a direct result of a penalty; if the offense commits a foul under the same scenario, the defensive team receives two points and a free kick. In all other circumstances (except for the open-ended and extremely rare unfair act clause), a penalty cannot exceed more than half the distance to the end zone. If the penalty would be less advantageous than the result of the actual play, then the team not committing the penalty can decline it.

In order to keep play moving, the offense must make a certain amount of progress (10 yards in most leagues) within a certain number of plays (3 in Canada, 4 in the United States), called downs. If the offense does indeed make this progress, a first down is achieved, and the team gets 3 or 4 more plays to achieve another 10 yards. If not, the offense loses possession to their opponent at the spot where the ball is. More commonly, however, the team on offense will, if they have a minimal chance of gaining a first down and have only one play left to do it (fourth down in the U.S., third down in Canada), attempt a scrimmage kick. There are two types of scrimmage kick: a punt is when the ball is released from the punter's hand and kicked downfield as close to the opponent's end zone as possible without entering it; the kicking team loses possession of the ball after the kick and the receiving team can attempt to advance the ball or call a fair catch. The other scrimmage kick is a field goal attempt. This must be attempted by place kick or (more rarely) drop kick, and if the kicked ball passes through the goal set at the edge of the opponent's end zone, the team scores three points. (Four-point field goals have been offered in a few variations of the game under special rules, but the NFL, college and high school football only offer three-point field goals.) In Canada, any kick that goes into the end zone and is not returned, whether it be a punt or a missed field goal, is awarded one single point.

If the team in possession of the ball, at any time, advances (either by carrying or catching) the ball into the opponent's end zone, it is a touchdown, and the team scores six points and a free play known as a try. In a try, a team attempts to score one or two points (rules vary by each league, but under standard rules, a field goal on a try is worth one point while another touchdown is worth two). At the college and professional levels, the defense can also score on a try, but only on the same scale (thus a botched try the defense returns for a touchdown scores only two points and not six). Kickoffs occur after every touchdown and field goal.

If a team is in its own end zone and commits a foul, is tackled with the ball, or bats, fumbles, kicks or throws the ball backward out of the field of play through the same end zone, the defense scores a safety, worth two points.

After a try, safety or field goal, the team that had possession of the ball goes back to the middle of the field and kicks the ball off to their opponent, and play continues as it did in the beginning of the game.

Play continues until halftime. (Each team switches their side of the field with the other halfway through each half, at the end of a quarter.) After the halftime break, a new kickoff occurs. Whichever team has more points at the end of the game is declared the winner; in the event of a tie, each league has its own rules for overtime to break the tie. Because of the nature of the game, pure sudden-death overtimes have been abolished at all levels of the game as of 2012.

At all adult levels of the game, a game is 60 timed minutes in length, split into four 15-minute quarters. (High school football uses 12-minute quarters, and the general rule is that the younger the players, the shorter the quarters typically are.) Because of the halftime, quarter breaks, time-outs, the minute warnings (two minutes before the end of a half in the NFL, three minutes in Canadian football), and frequent stoppages of the game clock (the clock stops, for example, after every incomplete pass and any time a ball goes out of bounds), the actual time it takes for a football game to be completed is typically over three hours in the NFL [23] and slightly under three hours in the CFL. [24]


According to 2017 study on brains of deceased gridiron football players, 99% of tested brains of NFL players, 88% of CFL players, 64% of semi-professional players, 91% of college football players, and 21% of high school football players had various stages of CTE. [25]

Other common injuries include injuries of legs, arms and lower back. [26] [27] [28] [29]

See also


  1. 1 2 "Gridiron football". Encyclopædia Britannica. Retrieved October 20, 2010.
  2. Jack Brimberg and William Hurley (2006). "Strategic considerations in the coaching of North American football". International Journal of Sport Management and Marketing. From International Journal of Sport Management and Marketing, Volume 1, Number 3, pp. 279–287.
  3. 1 2 3 4 Bernstein, Mark F. (2001). Football: The Ivy League Origins of an American Obsession. University of Pennsylvania Press. pp. 9–10. ISBN   978-0-8122-3627-9.
  4. Rielly, Edward J. (2009). Football: An Encyclopedia of Popular Culture . University of Nebraska Press. pp.  53–55, 285. ISBN   978-0-8032-2630-2. Canadian.
  5. Flaherty, David H.; Manning, Frank E. (2013). The Soft Tissues: Trauma and Sports Injuries. Butterworth-Heinemann. p. 402. ISBN   978-1-4832-8007-3.
  6. Steinberg, Shirley R. (2010-06-17). Boy Culture: An Encyclopedia. ABC-CLIO. pp. 156–157. ISBN   978-0-313-35081-8.
  7. Puhalla, Jim (2010). Sports Fields: Design, Construction, and Maintenance. John Wiley & Sons. p. 339. ISBN   978-0-470-43893-0.
  8. Mandelbaum, Michael (2005). The Meaning Of Sports. PublicAffairs. p. 26. ISBN   978-0-7867-3884-7.
  9. The Library of Work and Play: Outdoor Sports and Games by Claude H. Miller. Garden City, N.Y.: Doubleday, Page & Company, 1911
  10. "Gridiron, n. (3.e.)". Oxford English Dictionary . 1989. Retrieved October 20, 2010.
  11. Matt, Kohl (2017). "Pigskin and gridiron: notes on the American Football lexicon". Oxford University Press . Retrieved October 5, 2017.
  12. "IFAF Statutes 2016" (PDF). Archived from the original (PDF) on September 12, 2017.
  13. 1 2 History Staff (July 30, 2021). "Who Invented Football?". The History Channel . A&E Television Networks, LLC . Retrieved 16 February 2023.
  14. "Camp and His Followers: American Football 1876–1889" (PDF). The Journey to Camp: The Origins of American Football to 1889. Professional Football Researchers Association. Archived from the original (PDF) on September 29, 2010. Retrieved 2010-01-26.
  15. Bishop, LuAnn (18 November 2013). "11 Historic Tidbits About The Game". Yale News. Archived from the original on 2016-03-03. Retrieved 2017-01-24.
  16. Vancil, Mark (Ed.) (2000). ABC Sports College Football All-Time All-America Team. New York: Hyperion Books. p. 18. ISBN   978-0-7868-6710-3.
  17. Flaherty, David H.; Manning, Frank E. (1993). The Beaver Bites Back?: American Popular Culture in Canada. McGill–Queen's Press. p. 16. ISBN   978-0-7735-1120-0.
  18. "100th Grey Cup - Toronto - Grey Cup History Timeline 1900". Archived from the original on 2012-09-22. Retrieved 2015-01-18. History of the Grey Cup
  19. "The World's Highest-Paid Athletes 2020". Forbes .
  20. "The making of Patrick Mahomes, the highest-paid man in sports history". Sky Sports.
  21. "2018 Football Attendance" (PDF). NCAA. Archived (PDF) from the original on July 18, 2019.
  22. [ dead link ]
  23. Pelissero, Tom (March 24, 2017). "Exclusive: Roger Goodell says changes coming to quicken NFL games in 2017". USA Today. Retrieved March 24, 2017.
  24. "CFL pass interference replay hasn't been a problem". March 28, 2019. Retrieved March 28, 2019.
  25. "BU Researchers Find CTE in 99% of Former NFL Players Studied". Boston University. 26 July 2017.
  26. Willigenburg, N. W.; Borchers, J. R.; Quincy, R.; Kaeding, C. C.; Hewett, T. E. (2016). "Comparison of Injuries in American Collegiate Football and Club Rugby: A Prospective Cohort Study - Nienke W. Willigenburg, James R. Borchers, Richard Quincy, Christopher C. Kaeding, Timothy E. Hewett, 2016". The American Journal of Sports Medicine. 44 (3): 753–60. doi:10.1177/0363546515622389. PMID   26786902. S2CID   21829142.
  27. "Common Aches, Pains, and Injuries You Can Expect From Playing Football". Verywell Fit.
  28. Makovicka, J. L.; Patel, K. A.; Deckey, D. G.; Hassebrock, J. D.; Chung, A. S.; Tummala, S. V.; Hydrick, T. C.; Gulbrandsen, M.; Hartigan, D. E.; Chhabra, A. (2019). "Lower Back Injuries in National Collegiate Athletic Association Football Players: A 5-Season Epidemiological Study". Orthopaedic Journal of Sports Medicine. 7 (6). doi:10.1177/2325967119852625. PMC   6582304 . PMID   31245431.
  29. "10 Common Football Injuries". Revere Health.


Related Research Articles

<span class="mw-page-title-main">Canadian football</span> Canadian team sport

Canadian football, or simply football, is a sport in Canada in which two teams of 12 players each compete on a field 110 yards (101 m) long and 65 yards (59 m) wide, attempting to advance a pointed oval-shaped ball into the opposing team's end zone.

<span class="mw-page-title-main">End zone</span> Scoring area on the field in gridiron football

The end zone is the scoring area on the field, according to gridiron-based codes of football. It is the area between the end line and goal line bounded by the sidelines. There are two end zones, each being on the opposite side of the field. It is bordered on all sides by a white line indicating its beginning and end points, with orange, square pylons placed at each of the four corners as a visual aid. Canadian rule books use the terms goal area and dead line instead of end zone and end line respectively, but the latter terms are the more common in colloquial Canadian English. Unlike sports like association football and ice hockey which require the ball/puck to pass completely over the goal line to count as a score, both Canadian and American football merely need any part of the ball to break the vertical plane of the outer edge of the goal line.

<span class="mw-page-title-main">Forward pass</span> Gridiron football play

In several forms of football, a forward pass is the throwing of the ball in the direction in which the offensive team is trying to move, towards the defensive team's goal line. The legal and widespread use of the forward pass distinguishes gridiron football from rugby football from which the gridiron code evolved, in which the play is illegal.

<span class="mw-page-title-main">Snap (gridiron football)</span> Backward passing of the ball in gridiron football

A snap is the backward passing of the ball in gridiron football at the start of play from scrimmage.

<span class="mw-page-title-main">Line of scrimmage</span> Transverse line in American football

In gridiron football, a line of scrimmage is an imaginary transverse line beyond which a team cannot cross until the next play has begun. Its location is based on the spot where the ball is placed after the end of the most recent play and following the assessment of any penalty yards.

<span class="mw-page-title-main">Touch football (American)</span> Variant of American football

Touch football is an amateur variant of American football and Canadian football. The basic rules are similar to those of the mainstream game, but to end a down, the person carrying the ball need only be touched, instead of tackled, by a member of the opposite team. This rule change gave the game its name, to differentiate it from other variants. It is similar to street football, another amateur variant, however in street football full contact is allowed.

<span class="mw-page-title-main">Touchdown</span> Means of scoring in both American and Canadian football

A touchdown is a scoring play in gridiron football. Whether running, passing, returning a kickoff or punt, or recovering a turnover, a team scores a touchdown by advancing the ball into the opponent's end zone. More specifically a touchdown is when any part of the football, in the possession of an offensive player, crosses the goal line while the player, as well as the ball, is inbounds, and the player is upright. In order for a player to be down, any part of their body other than their hands or feet must touch the ground. If a player falls down without being contacted by a defensive player, whether or not they are down varies by league.

<span class="mw-page-title-main">Down (gridiron football)</span> Period in which a play transpires in gridiron football

A down is a period in which a play transpires in gridiron football. The down is a distinguishing characteristic of the game compared to other codes of football but is synonymous with a "tackle" in rugby league. The team in possession of the football has a limited number of downs to advance ten yards or more towards their opponent's goal line. If they fail to advance that far, possession of the ball is turned over to the other team. In most situations if a team reaches their final down, they will punt to their opponent, which forces their opponent to begin their drive from further down the field; if they are in range, they might instead attempt to score a field goal.

This is a glossary of terms used in Canadian football. The Glossary of American football article also covers many terms that are also used in the Canadian version of the game.

  1. Legally positioned at the kick-off or the snap. On kick-offs, members of the kicking team must be behind the kick-off line; members of the receiving team must be at least 10 yards from the kick-off line. On scrimmages, at the snap the offence must be behind the line of scrimmage; the defence must be at least one yard beyond the line of scrimmage.
  2. A player of the kicking team who can legally recover the kick. The kicker and any teammates behind the ball at the time of the kick are onside. Thus on kick-offs all players of the kicking team are onside, but on other kicks usually only the kicker is. The holder on a place kick is not considered onside.
  1. A defensive position on scrimmages, also called free safety. Typical formations include a single safety, whose main duty is to cover wide receivers. See also defensive back.
  2. A two-point score. The defence scores a safety when the offence carries or passes the ball into its own goal area and then fails to run, pass, or kick the ball back into the field of play; when this term is used in this sense, it is also referred to as a safety touch.
<span class="mw-page-title-main">Comparison of American and Canadian football</span> Differences between the two most common types of gridiron football

American and Canadian football are gridiron codes of football that are very similar; both have their origins partly in rugby football, but some key differences exist between the two codes.

<span class="mw-page-title-main">American football rules</span>

Gameplay in American football consists of a series of downs, individual plays of short duration, outside of which the ball is or is not in play. These can be plays from scrimmage – passes, runs, punts or field goal attempts – or free kicks such as kickoffs and fair catch kicks. Substitutions can be made between downs, which allows for a great deal of specialization as coaches choose the players best suited for each particular situation. During a play, each team should have no more than 11 players on the field, and each of them has specific tasks assigned for that specific play.

In gridiron football, clock management is an aspect of game strategy that focuses on the game clock and/or play clock to achieve a desired result, typically near the end of a match. Depending on the game situation, clock management may entail playing in a manner that either slows or quickens the time elapsed from the game clock, to either extend the match or hasten its end. When the desired outcome is to end the match quicker, it is analogous to "running out the clock" seen in many sports. Clock management strategies are a significant part of American football, where an elaborate set of rules dictates when the game clock stops between downs, and when it continues to run.

<span class="mw-page-title-main">Kickoff (gridiron football)</span> Method of starting a drive in gridiron football

A kickoff is a method of starting a drive in gridiron football. Additionally, it may refer to a kickoff time, the scheduled time of the first kickoff of a game. Typically, a kickoff consists of one team – the "kicking team" – kicking the ball to the opposing team – the "receiving team". The receiving team is then entitled to return the ball, i.e., attempt to advance it towards the kicking team's end zone, until the player with the ball is tackled by the kicking team, goes out of bounds, scores a touchdown, or the play is otherwise ruled dead. Kickoffs take place at the start of each half of play, the beginning of overtime in some overtime formats, and after scoring plays.

<span class="mw-page-title-main">Comparison of American football and rugby union</span>

A comparison of American football and rugby union is possible because of the games' shared origins, despite their dissimilarities.

A comparison between American football and rugby league is possible because of their shared origins and similar game concepts. Rugby league is arguably the most similar sport to American football after Canadian football: both sports involve the concept of a limited number of downs/tackles and scoring touchdowns/tries takes clear precedence over goal-kicking.

The following terms are used in American football, both conventional and indoor. Some of these terms are also in use in Canadian football; for a list of terms unique to that code, see Glossary of Canadian football.

<span class="mw-page-title-main">American football</span> Team field sport

American football, also known as gridiron football, is a team sport played by two teams of eleven players on a rectangular field with goalposts at each end. The offense, the team with possession of the oval-shaped football, attempts to advance down the field by running with the ball or passing it, while the defense, the team without possession of the ball, aims to stop the offense's advance and to take control of the ball for themselves. The offense must advance at least ten yards in four downs or plays; if they fail, they turn over the football to the defense, but if they succeed, they are given a new set of four downs to continue the drive. Points are scored primarily by advancing the ball into the opposing team's end zone for a touchdown or kicking the ball through the opponent's goalposts for a field goal. The team with the most points at the end of a game wins.

A comparison of Canadian football and rugby union is possible because of the games' shared origins, despite their dissimilarities.

<span class="mw-page-title-main">Punt (gridiron football)</span> Kick downfield to the opposing team in gridiron football

In gridiron football, a punt is a kick performed by dropping the ball from the hands and then kicking the ball before it hits the ground. The most common use of this tactic is to punt the ball downfield to the opposing team, usually on the final down, with the hope of giving the receiving team a field position that is more advantageous to the kicking team when possession changes. The result of a typical punt, barring any penalties or extraordinary circumstances, is a first down for the receiving team. A punt is not to be confused with a drop kick, a kick after the ball hits the ground, now rare in both American and Canadian football.