death knell vs uvula

death knell

noun
  • The tolling of a bell announcing death. 

  • A sign or omen foretelling the death or destruction of something. 

uvula

noun
  • an object so suspended inside a bell that it may hit the bell and cause it to ring; a clapper 

  • the slight elevation in the mucous membrane immediately behind the internal urethral orifice of the urinary bladder, caused by the middle lobe of the prostate 

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