affiliation vs rivalry

affiliation

noun
  • The relationship resulting from affiliating one thing with another. 

  • A club, society or umbrella organisation so formed, especially a trade union. 

  • The establishment of a child's paternity or maternity 

rivalry

noun
  • The characteristic of being a rivalrous good, such that it can be consumed or used by only one person at a time. 

  • An ongoing relationship between (usually two) rivals who compete for superiority. 

  • Any competition between two or more things or factors. 

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