bacterium vs utricle

bacterium

noun
  • A single-celled organism with cell walls but no nucleus or organelles. 

utricle

noun
  • The larger of the two fluid-filled cavities forming part of the membranous labyrinth in the vertebrate inner ear (the other being the saccule) and into which the semicircular canals open. It contains hair cells and otoliths which send signals to the brain concerning the orientation of the head. 

  • A dry indehiscent one-seeded fruit with thin membranous pericarp, similar to an achene and found in the beet and dock plants. 

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