corroboration vs turndown

corroboration

noun
  • That which corroborates. 

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

turndown

adj
  • Made to wear with the upper part turned down. 

  • Capable of being turned down, or decreased in intensity. 

noun
  • The operational range of a device 

  • A downturn. 

  • A rejection. 

  • A downward pointing extension to a vehicle muffler. 

  • The service of turning down the bedcovers and often leaving chocolates, etc., on the pillow. 

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