A billiard ball is a small, hard ball used in cue sports, such as carom billiards, pool, and snooker. The number, type, diameter, color, and pattern of the balls differ depending upon the specific game being played. Various particular ball properties such as hardness, friction coefficient, and resilience are important to accuracy.
Cue balls from (left to right): Russian pyramid and kaisa—68 mm (2+11⁄16 in) Carom—61.5 mm (2+7⁄16 in) International pool—57.15 mm (2+1⁄4 in) Snooker—52.5 mm (2+1⁄16 in) British-style pool—51 mm (2 in)
Carom balls. Four-ball needs an additional object ball.
Pool balls in a rack
Setup for blackball
A ball is a round object with several 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. Balls can also be used for simpler activities, such as catch or 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.
Group of balls
Russian leather balls (Russian: мячи), 12th-13th century.
Football from association football (soccer)
Handball
