American football, known in the United States as football, is a sport played between two teams of eleven. The objective of the game is to score points by advancing the ball into the opposing team's end zone. The ball can be advanced by running with it or throwing it to a teammate. Points can be scored by carrying the ball over the opponent's goal line, catching a pass thrown over that goal line, kicking the ball through the opponent's goal posts or tackling an opposing ball carrier in his own end zone.
In the United States, high school football, college football and professional football are played under slightly different rules. High school football is governed by theNational Federation of State High School Associations, college football by the National Collegiate Athletic Association and National Association of Intercollegiate Athletics, while the major professional league is the NFL.
The sport is also played in Europe, Japan and Mexico. The International Federation of American Football acts as an international governing body for the sport. American football is closely related to Canadian football but with some differences in rules and the field.