crawfish vs crayfish

crawfish

noun
  • Various marine crustaceans, rock lobster; especially Jasus lalandii, the Cape crawfish. 

  • Various freshwater crustaceans, crayfish. 

  • A slur against Anglo-Canadians used in some corners of Quebec (including the Gaspé). 

verb
  • To backpedal, desert or withdraw (also used with out). 

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 

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