convocation vs upper chamber

convocation

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

  • An assembly or meeting. 

  • The act of calling or assembling by summons. 

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

  • A flock of eagles. 

upper chamber

noun
  • The upper legislative chamber in a bicameral legislature; usually smaller and having more restricted power than the lower chamber. 

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