prelims vs prolog

prelims

noun
  • The preliminary front matter of a book, i.e. all content preceding the main text or work itself. 

  • Preliminary examinations taken as a whole, as sat by an individual or year group. 

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 prelims and prolog occurred in a corpus of books? (source: Google Ngram Viewer )