chapter house vs hegumen

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. 

hegumen

noun
  • The head of a monastery of the Eastern Orthodox Church or Eastern Catholic Churches. 

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