Pool, also more formally known as pocket billiards (mostly in North America) or pool billiards(mostly in Europe and Australia), is the family of cue sports and games played on a pool table having six receptacles called pockets along the rails, into which balls are deposited as the main goal of play. Popular versions include eight-ball and nine-ball. An obsolete term for pool is six-pocket.There are hundreds of pool games. Some of the more well known include eight-ball, nine-ball, ten-ball, straight pool, one-pocket and bank pool.There are also hybrid games combining aspects of both pool and carom billiards, such as American four-ball billiards, cowboy pool and bottle pool.