Meaning

noun any of various games played with a ball (round or oval) in which two teams try to kick or carry or propel the ball into each other's goal

noun the inflated oblong ball used in playing American football

originFrom Middle English fotbal, footbal, equivalent to foot + ball, because the ball was primarily manipulated with the feet in early versions of the game (though some modern varieties involve more handling than kicking). The name for the briefcase is a play on “dropkick”, the code name of an early version of the nuclear war plan.

Etymology from Wiktionary, CC BY-SA 3.0