An Etymological Dictionary of the German Language/Annotated/einst

by Friedrich Kluge

einst, adverb, from the equivalent Middle High German einst, einest, Old High German einêst, adverb, ‘once, at one time’; an obscure derivative of ein; in Anglo-Saxon œ̂nes, English once, to which Old High German eines, Middle High German eines, ‘once, at one time,’ also correspond. Compare Old High German anderes, anderêst, Middle High German anderes, anderst, ‘otherwise,’ as similar formations.