john vs water closet

john

noun
  • A device or place to urinate and defecate: now usually a toilet or lavatory, but also (dated) a chamber pot or outhouse. 

  • A male mule. 

  • A Western man traveling in East Asia. 

  • A prostitute's client. 

water closet

noun
  • A room containing a flush toilet. 

  • A flush toilet itself. 

  • Used other than figuratively or idiomatically: see water, closet. 

How often have the words john and water closet occurred in a corpus of books? (source: Google Ngram Viewer )