appendix vs preliminary

appendix

noun
  • A text added to the end of a book or an article, containing additional information. 

  • Any process, prolongation, or projection. 

  • The vermiform appendix. 

preliminary

noun
  • Any of a series of sports events that determine the finalists 

  • A preparation for a main matter; an introduction. 

  • A relatively minor contest that precedes a major one, especially in boxing 

adj
  • In preparation for the main matter; initial, introductory, preparatory. 

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