An Etymological Dictionary of the German Language/Annotated/Kappe
Kappe, feminine, ‘hood, cowl’; the meaning Middle High German kappe, feminine, upon which it is based, does not correspond very often with that of Modern High German, its usual signification being ‘a garment shaped like a cloak and fitted with a cowl as a covering for the head’; hence Tarnkappe, which has first been made current in Modern High German in this century through the revival by scholars of the Middle High German tornkappe (properly ‘the cloak that makes the wearer invisible’). Old High German chappa; Anglo-Saxon cœppe, ‘cloak,’ English cap. The double sense of the Middle High German word appears in the Middle Latin and Romance cappa, ‘cloak, cap,’ on which it is based (on the primary form câpa is based English cope, from Middle English cope, as well as Old Icelandic kápa, ‘cloak’). With regard to the meaning compare Modern French chape (cape), ‘cope, scabbard, sheath, case,’ and the derivatives chapeau, ‘hat,’ and chaperon, ‘cowl.’ The Middle Latin word was adopted by the more civilised classes of Europe, passing into Slavonic as well as into Romance and Teutonic. The word was not borrowed, or rather not naturalised before the 8th century, for an earlier borrowed term would have been *chapfa in Old High German and *kapfe in Middle High German — Compare Kapelle.