convocation vs symposium

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. 

symposium

noun
  • A conference or other meeting for discussion of a topic, especially one in which the participants make presentations. 

  • A drinking party in Ancient Greece, especially one with intellectual discussion. 

  • A collection of essays, articles or papers on a particular subject by a number of contributors. 

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