cloakroom vs operating theatre

cloakroom

noun
  • A room intended for holding luggage, as at an airport. 

  • A private lounge next to a legislative chamber. 

  • A room intended for holding guests' cloaks and other heavy outerwear, as at a theater or night club. 

  • A lavatory, now particularly a small secondary lavatory or a men's room. 

operating theatre

noun
  • A room in a hospital used for performing surgery (originally designed for operations in front of observers). 

How often have the words cloakroom and operating theatre occurred in a corpus of books? (source: Google Ngram Viewer )