congruity vs synchrony

congruity

noun
  • An instance or point of agreement or correspondence; a resemblance. 

  • The quality of agreeing; the quality of being suitable and appropriate. 

synchrony

noun
  • synchronicity, the state of two or more events occurring at the same time. 

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