break-off vs commencement

break-off

noun
  • The first shot in a game of snooker or other cue-game 

  • That which breaks off, or is broken off 

  • A break, discontinuance, or interruption 

verb
  • To play the first shot in a game of snooker 

commencement

noun
  • The first existence of anything; act or fact of commencing; the beginning. 

  • The day when degrees are conferred by colleges and universities upon students and others. 

  • A graduation ceremony, from a school, college or university. 

How often have the words break-off and commencement occurred in a corpus of books? (source: Google Ngram Viewer )