courtyard vs fourgon

courtyard

noun
  • An area, open to the sky, partially or wholly surrounded by walls or buildings. 

fourgon

noun
  • A polygon with four sides; a quadrilateral. 

  • A French baggage wagon. 

  • An ammunition wagon. 

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