convention vs town hall

convention

noun
  • The convening of a formal meeting. 

  • A formal agreement, contract, rule, or pact. 

  • A treaty or supplement to such. 

  • A meeting or gathering. 

  • A practice or procedure widely observed in a group, especially to facilitate social interaction; a custom. 

  • A formal deliberative assembly of mandated delegates. 

town hall

noun
  • A widely accessible meeting, particularly where the audience is allowed to interact with the speakers. 

  • A building that houses the local government offices of a town. 

  • The town council 

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