American football: a game played on a field of 100 yards long and 53 1/3 yards wide in which two teams of 11 players attempt to get an ovoid ball to the end of each other's territory.
Canadian football: a game played on a field of 110 yards long and 65 yards wide in which two teams of 12 players attempt to get an ovoid ball to the end of each other's territory.
Gaelic football: a field game played with similar rules to hurling, but using hands and feet rather than a stick, and a ball, similar to, yet smaller than a soccer ball.
From Middle English footbal, foteball, equivalent to , which may refer to the act of kicking a ball with the feet. The name for the briefcase is a play on “dropkick”, the code name of an early version of the nuclear war plan.{{cite-web
|title=Military aides still carry the president's nuclear 'football'