crayfish

{ , n.; pl. -fishes or -fish. [ Corrupted fr. OE. crevis, creves, OF. crevice, F. écrevisse, fr. OHG. krebiz crab, G. krebs. See Crab. The ending -fish arose from confusion with E. fish. ] (Zool.) Any decapod crustacean of the family Astacidæ (genera Cambarus and Cambarus), resembling the lobster, but smaller, and found in fresh waters. Crawfishes are esteemed very delicate food both in Europe and America. The North American species are numerous and mostly belong to the genus Cambarus. The blind crawfish of the Mammoth Cave is Cambarus pellucidus. The common European species is Astacus fluviatilis.
Syn. -- crawdad, crawdaddy. [ 1913 Webster ]

2. tiny lobsterlike crustaceans usually boiled briefly.
Syn. -- crawdad, ecrevisse. [ WordNet 1.5 ]

3. a large edible marine crustacean having a spiny carapace but lacking the large pincers of true lobsters.
Syn. -- spiny lobster, langouste, rock lobster, crayfish, sea crawfish. [ WordNet 1.5 ]