The original game of Billiards is hardly seen in America, but is the origin for most "
pool" games like
eight ball,
nine ball, and
snooker.
A billiard table looks a lot like a pool table, except for the fact that it has no pockets. Also, there are only three balls: your ball, your opponent's ball, and an object ball. They're usually colored something like red, yellow, white.
Games are usually played to a predetermined number of points, depending on the skill of the players. Getting a point is no easy task. You must strike your ball into either of the other balls, bank your ball off of three cushions, and then strike the third ball. This is referred to as "three-cushion billiards" and is very hard for beginners, who often start off with "one-cushion billiards".
Billiards requires being able to hit your ball off of another ball and maintain control of it. To some extent, the same rules apply to this type of shot as a bank shot...your ball will come away at roughly the same angle it went in (with some variation due to friction and momentum loss).
Hitting one ball off of another to make a shot is called a "billiard shot". This shot is vital to any billiards-style game, including pocket-billiards (pool).
If you want to see exactly how hard this game is try setting up a shot with just the cue ball and one other ball, hit the cue off of the ball and try to control where it will end up. Then try and control where it will end up after the billiard shot plus three banks.