hearing vs teach-in

hearing

noun
  • A proceeding at which discussions are heard. 

  • The sense used to perceive sound. 

  • The act by which something is heard. 

  • A legal procedure done before a judge, without a jury, as with an evidentiary hearing. 

adj
  • Able to hear, as opposed to deaf. 

teach-in

noun
  • An extended session of lectures or discussions on controversial topics as a form of protest. 

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