earmuff vs stethoscope

earmuff

noun
  • A sound-deadening cup or a pair of such cups worn over the ear or ears. 

  • A garment to keep the ears warm. 

  • A garment or part worn over a single ear. 

stethoscope

noun
  • A medical instrument used for listening to sounds produced within the body. 

verb
  • To auscultate, or examine, with a stethoscope. 

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