"kind of knitting done with a needle with a hook at one end," 1846, from French crochet "small hook; canine tooth" (12c.), diminutive of croc "hook," from Old Norse krokr "hook," which is of obscure origin but perhaps related to the widespread group of Germanic kr- words meaning "bent, hooked." So called for the hooked needle used. Crochet-needle is from 1848; crochet-work from 1856; crochet-hook from 1849.
"hooked, curved like a scythe or sickle," 1801, from Latin falcatus "sickle-shaped, hooked, curved," from falcem (nominative falx) "sickle," which is of uncertain origin, perhaps a borrowing from a non-Latin Indo-European language of Italy. De Vaan lists cognates as Old Irish delg "thorn, pin," Welsh dala "sting," Lithuanian dilgė "nettle," Old Norse dalkr "pin, spine, dagger," Old English delg "clasp." Related: Falcated; falcation; falciform (1766).
c. 1200, "hook-shaped instrument or weapon; tool or utensil consisting of or having as an essential component a hook or curved piece of metal," from Old Norse krokr "hook, corner," cognate with Old High German kracho "hooked tool," of obscure origin but perhaps related to the widespread group of Germanic kr- words meaning "bent, hooked." If there was an Old English *croc it has not been found.
From late 14c. as "a bend or curved part;" late 15c. as "any bend, turn, or curve." From mid-15c. as "a shepherd's staff with a curved top." Meaning "swindler" is American English, 1879, from crooked in figurative sense of "dishonest, crooked in conduct" (1708). Crook "dishonest trick" was in Middle English, especially in reference to the wiles of the Devil.