ending vs preface

ending

noun
  • A termination or conclusion. 

  • The last part of something. 

  • The last morpheme of a word, added to some base to make an inflected form (such as -s in "dogs"). 

preface

verb
  • To give a preface to. 

  • To introduce or make a comment before (the main point). 

noun
  • An introduction, or series of preliminary remarks. 

  • A title or epithet. 

  • The beginning or introductory portion that comes before the main text of a document or book. 

  • The prelude or introduction to the canon of the Mass. 

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