alliance vs concomitance

alliance

noun
  • The act of allying or uniting. 

  • Marriage. 

  • The persons or parties allied. 

  • The state of being allied. 

  • A union or connection of interests between families, states, parties, etc., especially between families by marriage and states by compact, treaty, or league. 

  • Any union resembling that of families or states; union by relationship in qualities; affinity. 

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 alliance and concomitance occurred in a corpus of books? (source: Google Ngram Viewer )