certify vs sanction

certify

verb
  • To authenticate or verify in writing. 

  • To attest that a product, service, organization, or person has met an official standard. 

  • To attest to (a fact) as the truth. 

sanction

verb
  • To ratify; to make valid. 

  • To penalize (a state etc.) with sanctions. 

  • To give official authorization or approval to; to countenance. 

noun
  • An approval, by an authority, generally one that makes something valid. 

  • A penalty, punishment, or some coercive measure, intended to ensure compliance; especially one adopted by several nations, or by an international body. 

  • A law, treaty, or contract, or a clause within a law, treaty, or contract, specifying any of the above. 

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