"Billiard games" is a general name for a variety of games such as snooker, pool, 8-ball and balkline. All of these billiards games share similar equipment - a long rectangular table, balls and a stick - but they differ from each other in their goals and styles of play. This article deals with the different types of billiards games and the differences between them.
Carom Games vs. Pocket Games
Billiards basic distinction is between the carom games and the pocket games.
Carom games are played on pocket-less tables with no more than three balls. The object of the carom games is to achieve highest score by causing the cue ball to carom on and off the object balls. The most known carom games are straight billiards, balkline and three cushion billiard. These carom games are usually played professionally in Europe, Asia and South America and rarely across the States.

Pocket billiard games, known also as pool games, are played on pocketed table, with three pockets on each side of the table; four corner pockets and two side pockets. The object of most of the pocket billiard games is to cause the object balls to sink into the pockets. The most popular pocket billiard games are straight pool, snooker and 8-ball pool which are especially popular in the US and UK.

Just for your knowledge, even though snooker is played on a pocketed pool table, when people talk about pocket billiard games they refer to straight pool, 8-ball, 9-ball and other popular pool games but not to snooker. Snooker is considered as a separate unit.