crayfish vs crustacean

crayfish

noun
  • A rock lobster (family Palinuridae). 

  • Any of numerous freshwater decapod crustaceans in superfamily Astacoidea or Parastacoidea, resembling the related lobster but usually much smaller. 

  • The species Thenus orientalis of the slipper lobster family (Scyllaridae). 

  • A freshwater crustacean (family Cambaridae), sometimes used as an inexpensive seafood or as fish bait. 

  • A freshwater crayfish (family Parastacidae), such as the gilgie, marron, or yabby. 

verb
  • to catch crayfish 

crustacean

noun
  • Any arthropod of the subphylum Crustacea, including lobsters, crabs, shrimp, barnacles and woodlice. 

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