backstair vs buttery

backstair

adj
  • clandestine, secret or furtive 

noun
  • The backstairs (stairs at the rear of a building). 

buttery

adj
  • Marked by insincere flattery; obsequious. 

  • Made with or tasting of butter. 

  • Resembling butter in some way, such as yellow color or smooth texture. 

noun
  • A room in a university where snacks are sold. 

  • A room for keeping food or beverages; a storeroom. 

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