Gridiron football, or
North American football, is
football primarily played in the
United States and
Canada. The predominant forms of gridiron football are
American football and
Canadian football. Gridiron refers to the sport's characteristic
playing field, which is marked with a series of parallel lines resembling a
gridiron.
"Gridiron" football developed in the late 19th century out of the older games related to the games now known as
rugby football and
association football. It is distinguished from other football codes by its use of helmets and shoulder pads, the
forward pass, the
system of downs, a
line of scrimmage, more specialist
positions and
formations, free substitution, platooning of different players for offense and defense, measurements in
yards, a distinctive brown leather
ball in the shape of a
prolate spheroid, 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 international governing body for gridiron football is the
International Federation of American Football (IFAF); although the organization uses the name "American football" and 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.