In mathematics, a ball is the space bounded by a sphere.
A billiard ball is a small, hard ball used in cue sports, such as carom billiards, pool, and snooker.
Cowboy pool (or simply cowboy) is a hybrid pool game combining elements of English billiards through an intermediary game, with more standard pocket billiards characteristics.
Four-ball billiards (often abbreviated to simply four-ball, and sometimes spelled 4-ball or fourball) is a carom billiards game, played on a pocketless table with four billiard balls, usually two red and two white, one of the latter with a spot to distinguish it (in some sets, one of the white balls is yellow instead of spotted).
Fourball is a playing format in the sport of golf.