cockle vs shellfish

cockle

noun
  • The shell of such a mollusk. 

  • The fire chamber of a furnace. 

  • The mineral black tourmaline or schorl. 

  • Any of various edible European bivalve mollusks, of the family Cardiidae, having heart-shaped shells. 

  • A wrinkle, pucker 

  • The dome of a heating furnace. 

  • One’s innermost feelings (only in the expression “the cockles of one’s heart”). 

  • A £10 note; a tenner. 

  • A kiln for drying hops; an oast. 

  • A defect in sheepskin; firm dark nodules caused by the bites of keds on live sheep 

  • Any of several field weeds, such as the common corncockle (Agrostemma githago) and darnel ryegrass (Lolium temulentum). 

verb
  • To cause to contract into wrinkles or ridges, as some kinds of cloth after a wetting; to pucker. 

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 cockle and shellfish occurred in a corpus of books? (source: Google Ngram Viewer )