Probably from *kréh₂-tis (“fenced handiwork”), possibly of substrate origin; compare Proto-Germanic *hurdiz (“wickerwork door or frame, hurdle”), Old Prussian corto (“fence”).
Other theories derive the word from Proto-Indo-European *kr̥tis, from a root *kert- (“to weave, twist together”); if so, compare Latin crassus, Sanskrit कृत् (kṛt, “to spin”), and, according to Witzel, Sanskrit कवि (kavi, “reins, ladle”). However, the connection to *kert- is implicitly denied by De Vaan. The connection with Ancient Greek κύρτος (kúrtos, “weel, lobster pot”) has also been dismissed by R. S. P. Beekes.