Gridiron football

An American gridiron football field. The Canadian field differs slightly in dimensions and design, but is essentially similar. The numbers on the field indicate the number of yards to the nearest end zone.

Gridiron football (or more commonly, just "gridiron") is an umbrella term used in some countries outside North America to refer to several codes of football played primarily in Northern America.^{[citation needed]} The term refers to the sport's characteristic field of play, which is marked with a series of parallel lines resembling a gridiron.

Gridiron football is distinguished from other football codes by its use of heavy protective equipment, the forward pass, the system of downs, a line of scrimmage, distinct positions and formations, and the ability to score points while not in possession of the ball (by way of the safety). Walter Camp is credited with creating many of the rules that differentiate gridiron football from its older counterparts. The game descends from rugby football, itself an umbrella term for various similar codes (union, league and sevens).^{[citation needed]}

• American football is the most common and widely known of the gridiron football codes. It is played with eleven men to a side, four downs and a 100-yard field. It is one of the most popular sports in the United States.
• Canadian football is played almost exclusively in Canada. It was originally more closely related to rugby until the Burnside rules brought the game closer to its American counterpart. The game is played on a 110-yard field and has three downs and twelve men to a side. The Canadian game also allows players to move forward toward the line of scrimmage before the snap, which is forbidden in most versions of American football, and also features a one-point "single" for kicking a ball into the end zone (otherwise only present in Australian rules football).
• Nine-man football, eight-man football and six-man football are varieties of gridiron football played with fewer players. They are played with four downs (often with a 15 yard requirement for a new set of downs, as opposed to 10 in other codes), fewer offensive linemen, and an 80-yard field.
• Indoor football is played with special rules to accommodate smaller indoor facilities. It is played on a 50-yard field with seven or eight men to a side. It was first invented in 1932 but did not gain popularity until James F. Foster's proprietary version, arena football, debuted in 1986.
• Touch football, flag football and backyard football are informal varieties of the game, played primarily at an amateur and unorganized level.

According to certain early rules of American football, some fields were painted with square-like "grids" of demarcation. The ball would be snapped in the grid in which it was downed on the previous play. This was abandoned in favor of the system of yard lines and hash marks now used. An example of a field that was painted with such a grid pattern is the old Archbold Stadium at Syracuse University, which has since been torn down.^[1]

The word gridiron alone may refer either to the field or to the sport; however, in North America it is mostly used in reference to the field, usually in a somewhat figurative or poetic sense. In some other English-speaking countries—particularly Australia and New Zealand—it is the primary term used to refer to the sport, differentiating it from other forms of football such as Australian football, association football (soccer), rugby league, and rugby union.^[2] In the United Kingdom the most frequently used term is American football, but gridiron is also used to describe the game.^[3]