cray·fish (krāfĭsh′) also craw·fish (krô-)
n. pl. crayfish or cray·fish·es also crawfish or craw·fish·es
1. Any of various freshwater crustaceans of the families Astacidae and Cambaridae of the Northern Hemisphere and the family Parastacidae of the Southern Hemisphere, resembling a lobster but considerably smaller. Also called mudbug; also called regionally crawdad.
2. See spiny lobster.
[By folk etymology from Middle English crevise, from Old French crevice, perhaps from Old High German krebiz, edible crustacean; see gerbh- in the Appendix of Indo-European roots.]
Word History: The crayfish, also known as the crawfish, owes its name to a misunderstanding. The actual source of the word may be the Old High German word krebiz, "edible crustacean," or a word related to it. From this Germanic source came Old French crevice, which when taken into English became crevise (first recorded in a document written in 1311-1312). In Old French and Middle English these words designated the crayfish. People began to pronounce and spell the last part of this word as if it were fish, the first fish spelling being recorded in 1555. Because of a variation in Anglo-Norman pronunciation, two forms of the word have come down to Modern English: crayfish and crawfish.
The American Heritage® Dictionary of the English Language, Fifth Edition copyright ©2018 by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Indo-European & Semitic Roots Appendices
Thousands of entries in the dictionary include etymologies that trace their origins back to reconstructed proto-languages. You can obtain more information about these forms in our online appendices:
The Indo-European appendix covers nearly half of the Indo-European roots that have left their mark on English words. A more complete treatment of Indo-European roots and the English words derived from them is available in our Dictionary of Indo-European Roots.