bell button vs uvula

bell button

noun
  • A button in the form of a jingle bell, used as a fastener or decoration on a piece of clothing. 

  • A small, round mechanical device which, when pressed, rings a bell to announce one's presence or call a servant, assistant, etc. 

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 bell button and uvula occurred in a corpus of books? (source: Google Ngram Viewer )