affiliation vs concomitance

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 

concomitance

noun
  • occurrence or existence together or in connection with one another, coexistence 

  • A concomitant. 

  • The Roman Catholic doctrine of the existence of the entire body of Christ in the Eucharist, under each element, so that the body and blood are both received by communication in one kind only. 

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