congruency vs synchronicity

congruency

noun
  • The state of being congruent 

  • The quality of agreeing; being suitable and appropriate 

synchronicity

noun
  • The state of being synchronous or simultaneous. 

  • Coincidences that seem to be meaningfully related; supposedly the result of "universal forces". 

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