gill vs shellfish

gill

noun
  • A breathing organ of fish and other aquatic animals. 

  • A gill slit or gill cover. 

  • One of the combs of closely ranged steel pins which divide the ribbons of flax fiber or wool into fewer parallel filaments. 

  • The fleshy flap that hangs below the beak of a fowl; a wattle. 

  • One of the radial folds on the underside of the cap of a mushroom, the surface of which bears the spore-producing organs. 

  • ravine 

  • a two-wheeled frame for transporting timber 

  • rivulet 

  • a female ferret 

  • The flesh under or about the chin; a wattle. 

  • A drink measure for spirits and wine, approximately a quarter of a pint, but varying regionally. 

verb
  • To be or become entangled in a gillnet. 

  • To catch (a fish) in a gillnet. 

  • To remove the gills from a fish as part of gutting and cleaning it. 

shellfish

noun
  • A fisheries and colloquial term for an aquatic invertebrate having an inner or outer shell, such as a mollusc or crustacean, especially when edible. 

  • A culinary and nutritional term for several groups of non-piscine, non-tetrapod, aquatic animals that are used as a food source. The term often exclusively refers to edible aquatic crustaceans, bivalve mollusks and cephalopod mollusks; but sometimes echinoderms may be included as well. 

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