conventicle vs convocation

conventicle

noun
  • The place where such a meeting is held. 

  • A secret, unauthorized or illegal religious meeting. 

  • A Quaker meetinghouse. 

verb
  • To hold a secret, unauthorized or illegal religious meeting. 

convocation

noun
  • An assembly or meeting. 

  • The act of calling or assembling by summons. 

  • An assembly of the clergy, by their representatives, to consult on ecclesiastical affairs. 

  • An academic assembly, in which the business of a university is transacted. 

  • A flock of eagles. 

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