chapter house vs charterhouse

chapter house

noun
  • A building attached to a cathedral, church, or monastery and used as a meeting place. 

  • A building used by a sorority or fraternity as a residence or meeting place. 

charterhouse

noun
  • A Carthusian monastery. 

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