refresher vs renovation

refresher

noun
  • A review to refresh or renew knowledge. 

  • An equity grant given by a company to an existing employee, as opposed to an initial grant given to new employees. 

  • A fee paid to counsel to continue with a case, especially one that was adjourned. 

  • Something that refreshes. 

renovation

noun
  • An act, or the process, of renovating. 

  • Regeneration. 

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