fourgon vs rectangle

fourgon

noun
  • A polygon with four sides; a quadrilateral. 

  • A French baggage wagon. 

  • An ammunition wagon. 

rectangle

noun
  • Any quadrilateral having opposing sides parallel and four right angles. 

  • Such a quadrilateral that is oblong (longer than it is wide): one that is not regular (equilateral), that is, any except a square. 

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