Billiards, family of games played on rectangular tables twice as long as they are wide, with balls propelled by tapered, leather-tipped rods called cues. Lining the perimeter of the tables are rubber cushions from which the balls rebound. Tables range in size from 0.9 to 1.8 m (3 to 6 ft) wide and from 1.8 to 3.6 m (6 to 12 ft) long. The level table surface, called the bed, is most often made of slate and is covered with a finely woven fabric, usually green in color. A typical cue is 145 cm (57 in) long, weighs 538 g (19 oz), and has a tip diameter of 1.2 cm (0.5 in). Balls, once made of ivory, are now composed of a hard compound and range in size from about 5 cm (2 in) to 6 cm (2.4 in). The white ball that the player strikes with the tip of the cue is the cue ball. Other balls, which may be colored, are called object balls.
Two styles of play predominate. One requires tables with openings, called pockets, at the corners and at the midpoints of the long cushions. The other requires tables without openings. On a pocket table, the goal is to drive object balls into pockets with the cue ball. On a pocketless table, points are scored by caroming the cue ball off one ball into another, sometimes with cushion contact required of the cue ball. Carom games on pocketless tables predominate in continental Europe, Latin America, and Asia. Pocket games, which include pool, predominate in English-speaking countries. The international governing body of billiards is the World Confederation of Billiard Sports, located in Basel, Switzerland. The ruling body of the sport in the United States is the Billiard Congress of America, with headquarters and a hall of fame in Iowa City, Iowa. In the United States billiards is one of the most popular participant sports.