RACK EM AND BREAK!
The word "Pool" means and collective of money or ante. Many non-billiard games, such as poker, involve a pool but it was pocket billiards that the name became attached to. Another interesting fact is that the term "pool room" now means a place where pool is played, but in the 19th century a pool room was a betting parlor for horse racing. Pool tables were installed so patrons could pass time between races. The two became connected in the public mind, but the unsavory connotation of "pool room" came from the betting that took place there, not from billiards.