Billiardball

Billiardball is the term used for the spherical balls used in cue sports such as billiards, pool, and related games. Balls are struck with a cue on a cloth-covered table and are divided into the cue ball, which is struck by the player, and the object balls that are aimed to be potted or driven into pockets according to the rules of the game. In many pool games, the 15 object balls are numbered and divided into solid and striped groups, with the 8-ball typically being black.

Construction and materials have evolved over time. Historically, billiard balls were made from ivory, but since the late 19th century synthetic materials have become standard. Modern billiardballs are typically produced from phenolic resin or other durable plastics to provide uniform density, hardness, and consistent bounce, while minimizing table wear. Some sets may use alternative plastics or composite cores, but the goal is consistent performance across all balls.

Size and weight vary by game, but the most common specification for pool and billiards sets is a diameter of 2 1/4 inches (57.15 millimeters) and a weight of about 5.5 to 6.0 ounces (156–170 grams). Carom or continental billiard sets generally use slightly larger balls, around 61.5 millimeters (about 2.42 inches) in diameter.

Color, markings, and identification follow the rules of each discipline. Object balls are colored and numbered for easy recognition; the cue ball is white and may be unnumbered, while the eight ball in eight-ball play is typically black. Ball specifications are standardized by governing bodies for the respective cue sports to ensure uniform play.