commencement vs conclusion

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. 

conclusion

noun
  • The outcome or result of a process or act. 

  • The end or close of a pleading, for example, the formal ending of an indictment, "against the peace", etc. 

  • In an argument or syllogism, the proposition that follows as a necessary consequence of the premises. 

  • A decision reached after careful thought. 

  • An estoppel or bar by which a person is held to a particular position. 

  • The end, finish, close or last part of something. 

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