Billiards refers to a variety of games played on a rectangular table with a set number of tiny balls and a long stick known as a cue. The term comes from the French word billard, which means "ball" or "sphere." Pool is the most popular form of billiards. Other forms include carom billiards and snooker. Carom billiards is similar to pool in that it uses balls and a stick but it has rules that differ significantly from those of pool. For example, in carom billiards the object is not to get rid of all the balls but instead to shoot them into specific holes in the floor or wall. Snooker is a game similar to pool in that it involves shooting balls at a rack of pockets but with some important differences. The main difference between snooker and pool is that in snooker there are no empty spaces on the table; all the balls are solid spheres. Also, while in pool you can only shoot into numbered pockets, in snooker you can also shoot into unnumbered areas behind objects on the table (known as free shots). There are several different types of cues used in billiards.