hearing vs prolegomenon

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. 

prolegomenon

noun
  • A prefatory discussion; a formal essay or critical discussion serving to introduce and interpret an extended work. 

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