ending vs proem

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"). 

proem

noun
  • An introduction, preface or preamble. 

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