An Etymological Dictionary of the German Language/Annotated/Rock
Rock, masculine, ‘coat, robe, petticoat,’ from Middle High German roc (genitive rockes), Old High German rocch, masculine, ‘outer garment, coat’; corresponding to the equivalent Dutch rok, Old Frisian rok, Anglo-Saxon rocc, Old Icelandic rokkr; the implied Gothic *rukka- is wanting. From the Teutonic cognates is derived the Romance class, French rochet, ‘surplice’ (Middle Latin roccus, ‘coat’), which again passed into English (rochet). The early history of the Teutonic cognates is obscure; allied to Rocken?.