pocket billiards vs pocket pool

pocket billiards

noun
  • Synonym of pocket pool 

  • Any of a family of billiards games played on a specific class of billiards table, having six receptacles called pockets along the rails, in which balls are deposited as the main goal of play. 

pocket pool

noun
  • A variation of the game of pool. 

  • The act of manipulating one's genitalia through a trouser pocket; masturbation. 

How often have the words pocket billiards and pocket pool occurred in a corpus of books? (source: Google Ngram Viewer )