cochlea vs cotton wool bud

cochlea

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

  • 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. 

cotton wool bud

noun
  • A short, thin and flexible rod with a small wad of cotton wool at each end. 

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