concomitance vs congruency

concomitance

noun
  • A concomitant. 

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

  • 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. 

congruency

noun
  • The state of being congruent 

  • The quality of agreeing; being suitable and appropriate 

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