Gridiron football



Gridiron football is an umbrella term used to refer to several similar codes of football played primarily in the United States and Canada. The term refers to the sport's characteristic field of play, which is marked with a series of parallel lines resembling a gridiron. The term Gridiron, although rarely used to describe the sport in Anglo-America (where the sport is more commonly known simply as "football", but "gridiron" is occasionally used to refer to the field by itself), is most commonly used in areas outside the United States and Canada, particularly Australia and New Zealand, and to a lesser extent in Great Britain.

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, free substitution/platooning (the use of different players for offense and defense), measurements in the U.S. customary units of yards instead of meters (even in Canada, where the metric system remains standard for all other uses), 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.