An Etymological Dictionary of the German Language/Annotated/auch

by Friedrich Kluge

auch, adverb and conjunction, ‘also, likewise,’ from Middle High German ouch, Old High German ouh, ‘and, also, but.’ It corresponds to Old Saxon ôk, Dutch ook; OFries. âk, Anglo-Saxon eác, English eke, Old Icelandic auk, ‘besides,’ Danish og, ‘and, also, but,’ Swedish och, Icelandic ok; Gothic auk, ‘then, but’; an adverb common to Teutonic. Some refer this auk to the Teutonic root auk (Aryan aug), ‘to increase,’ whence Old High German ouhhôn, ‘to add,’ Old Saxon òkian, Anglo-Saxon ŷcan, Old Icelandic auka, Gothic aukan, ‘to increase,’ are derived (Latin augere, aug-ustus, Sanscrit ugrás, ‘powerful,’ ôjas, ‘strength,’ are allied to them); compare Anglo-Saxon tô-eácan, ‘moreover, also.’ Others trace Teutonic auk to a compound of two Aryan particles, au and ge (Greek αὖ, γε).