cochlea vs earphones

cochlea

noun
  • The complex, spirally coiled, tapered cavity of the inner ear of higher vertebrates, which contains the organ of Corti and in which sound vibrations are converted into nerve impulses. 

  • A spiral-shaped shell, especially that of a snail. 

earphones

noun
  • A pair of small loudspeakers worn inside each outer ear or covering all or part of the ear, without a connecting band worn over head. 

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