A
ball is a round, usually
spherical but sometimes
ovoid, object with various uses. It is used in
ball games, where the play of the game follows the state of the ball as it is hit, kicked or thrown by players. In the context of sports, "ball" need not refer to a spherical object, as is the case in
American football. Balls can also be used for simpler activities, such as catch,
marbles and
juggling. Balls made from hard-wearing materials are used in
engineering applications to provide very low friction bearings, known as
ball bearings.
Black-powder weapons use stone and metal balls as
projectiles.