An Etymological Dictionary of the German Language/Annotated/auf

by Friedrich Kluge

auf, adverb, preposition, ‘up, upwards, on, upon,’ from Middle High German and Old High German ûf, adverb, preposition, ‘upon’; corresponds to Old Saxon ûp, Anglo-Saxon ûp-ū̆pp, and its equivalent English up; Gothic iup, adverb, ‘upwards, aloft,’ differs remarkably in its vowel. Probably primitively Teutonic *ū̆ppa, ‘up,’ is allied to oben and über.