There are three major subdivisions of games within cue sports:
– Carom billiards, played on tables without pockets, typically ten feet in length, including straight rail, balkline, one-cushion carom, three-cushion billiards, artistic billiards, and four-ball.
– Pocket billiards (or pool), played on six-pocket tables of seven, eight, nine, or ten-foot length, including among others eight-ball (the world’s most widely played cue sport, nine-ball (the dominant professional game), ten-ball, straight pool (the formerly dominant pro game), one-pocket, and bank pool
– Snooker, English billiards, and Russian pyramid, played on a large, six-pocket table (dimensions just under 12 ft by 6 ft), all of which are classified separately from pool based on distinct development histories, player culture, rules, and terminology.
[From Wikipedia]