ending vs initiation

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"). 

initiation

noun
  • 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. 

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

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