An Etymological Dictionary of the German Language/Annotated/Kappes
Kappes, Kappus, masculine, ‘headed cabbage,’ from the equivalent Middle High German kappaȥ, kappûs, kabeȥ, masculine Old High German chabuȥ, chapuȥ, directly connected with Latin caput, which strangely enough does not appear in Middle Latin in the sense of ‘cabbage-head’; Italian capuccio (hence French cabus and English cabbage) presumes, however, a Middle Latin derivative of caput in the sense of ‘cabbage-head, headed cabbage.’ The naturalisation of the Italian word in High German may have been completed in the 7th century or so; by that time a number of Latin names of plants, as well as the art of cookery and gardening introduced from the South, was already firmly established in Germany.