initiation vs prolog

initiation

noun
  • The act of initiating, or the process of being initiated or introduced 

  • The first step of transcription or of transduction. 

  • The form or ceremony by which a person is introduced into any society; mode of entrance into an organized body; especially, the rite of admission into a secret society or order. 

prolog

noun
  • A speech or section used as an introduction, especially to a play or novel. 

  • A component of a computer program that prepares the computer to execute a routine. 

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