All about Football Football is the word given to a number of similar team sports, all of which involve (to varying degrees) kicking a ball with the foot in an attempt to score a goal. The most popular of these sports worldwide is association football, more commonly known as just "football" or "soccer".
The English language word "football" is also applied to "gridiron football" (a name associated with the North American sports, especially American football and Canadian football), Australian football, Gaelic football, rugby league, rugby union, and related games. Each of these codes (specific sets of rules, or the games defined by them) is referred to as "football".
These games involve:
* Two teams of usually between 11 and 18 players; some variations that have fewer players (five or more per team) are also popular
* a clearly defined area in which to play the game;
* scoring goals and/or points, by moving the ball to an opposing team's end of the field and either into a goal area, or over a line;
* goals and/or points resulting from players putting the ball between two goalposts
* the goal and/or line being defended by the opposing team;
* players being required to move the ball—depending on the code—by kicking, carrying and/or hand passing the ball; and
* players using only their body to move the ball.
In most codes, there are rules restricting the movement of players offside, and players scoring a goal must put the ball either under or over a crossbar between the goalposts. Other features common to several football codes include: points being mostly scored by players carrying the ball across the goal line and; players receiving a free kick after they take a mark/make a fair catch.
Peoples from around the world have played games which involved kicking and/or carrying a ball, since ancient times. However, most of the modern codes of football have their origins in England.
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, particularly Australia, New Zealand and 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) 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.
* 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 a ball kicked into the end zone and not returned by the receiving team.
* 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 60-yard field with ten or eleven 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.
 Origin of the Gridiron
According to the early rules of American football, fields were marked in a checkerboard pattern of grids. The ball would be snapped in the grid in which it was downed on the previous play. This system was abandoned in favor of the system of yard lines and hash marks now used.
As described in Outdoor Sports and Games (1911):
A football field is 330 feet long by 160 feet wide. At each end are goal posts set 18 feet 6 inches apart, with a crossbar 10 feet above the ground. The field is marked off in chalk lines similar to a tennis court, these lines being 5 yards apart. The centre of the field where the play starts is 55 yards from either end. It is usually customary to run lines parallel to the sides of the field, also 5 yards apart, but as a field is but 160 feet wide the first and last of these lines are but 5 feet from the side lines instead of 5 yards. The lines on a football field make a checkerboard effect and have given to the field the name of "gridiron."
An example of a field that was marked in the original gridiron pattern was the old Archbold Stadium at Syracuse University, which has since been torn down.
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. In the United Kingdom the most frequently used term is American football, but gridiron is also used to describe the game.