Football is a family of team sports that involve, to varying degrees, kicking a ball with a foot to score a goal . Unqualified, the word football is understood to refer to whichever form of football is the most popular in the regional context in which the word appears. Common rules among the sports include: [12] 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 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 or points resulting from players putting the ball between two goalposts. The goal or line being defended by the opposing team. Players being required to move the ball—depending on the code—by kicking, carrying, or hand-passing the ball. Players using o...