You know the game pool, yer?
Why is it called pool? :S
Any answer is appreciated!

Outside the cue sports industry, pocket billiards is almost exclusively referred to as ''pool,'' due to a perhaps unfortunate association with the ''poolrooms'' where gamblers ''pooled'' their money to bet remotely (''off-track'') on horse races. Because these venues often provided billiard tables, the term ''pool'' became synonymous with billiards, and though the original ''pool'' game was played on a pocketless table, the name stuck to pocket billiards as it gained in popularity.

http://home.kc.rr.com/pplofkc/origin.html

gives a believable description

As a generalization, the word “pool” is thought of as the common man’s term for billiards & this time we look to another sport on which people often wager their hard-earned money, horse racing! In the first incarnation of off-track betting men would gather in rooms to put their money together (or “pool” it) to figure out what the odds would be. Naturally, these places came to be known as “poolrooms.” To help entertain the men while they were waiting for races to begin these rooms usually had billiard tables. So interestingly, the name of the room came before the name of the game!