chou n.

"cabbage," a dialectal survival of Middle English col, from late Old English cawel, or perhaps from or influenced by cognate Old Norse kal. Both words are from Latin caulis "stem, stalk" (which in Vulgar Latin replaced brassica as the usual word for "cabbage"), from Proto-Italic *kauli- "stalk," from PIE root *(s)kehuli- "stem of a plant, stalk" (source also of Old Irish cual "faggot, bundle of sticks," Greek kaulos "stem, stalk, pole," Armenian c'awl "stalk, straw," Old Prussian kaulan, Lithuanian káulas "bone").

Latin caulis "cabbage" is the source also of Italian cavolo, Spanish col, Old French chol, French chou; it also was borrowed elsewhere in Germanic, for example Swedish kål, Danish kaal, German Kohl, Dutch kool.