corroboration vs verification

corroboration

noun
  • That which corroborates. 

  • The act of corroborating, strengthening, or confirming; addition of strength; confirmation 

verification

noun
  • The state of being verified. 

  • Confirmation; authentication. 

  • A formal phrase used in concluding a plea, to denote confirmation by evidence. 

  • The operation of testing the equation of a problem, to see whether it truly expresses the conditions of the problem. 

  • The act of verifying. 

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