commencement vs showtime

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. 

showtime

noun
  • The time for action. 

  • The time at which an entertainment event is set to begin. 

intj
  • A declaration that something is about to happen, particularly that the person speaking is about to act. 

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