An Etymological Dictionary of the German Language/Annotated/zwischen
zwischen, adverb and afterwards preposition, ‘between, among,’ from the equivalent Middle High German zwischen, zwüschen, adverb and preposition Originally a shortened form of the adverbial expressions Middle High German inzwischen, under zwischen, Old High German in zwiskên, untar zwiskên, ‘between each pair.’ Allied to Middle High German zwisc, zwisch, adjective, Old High German zwisk, zwiski, adjective, ‘twofold, two and two’; compare Old Saxon twisk, Dutch tusschen, English betwixt.—Derivatives Modern High German dazwischen, inzwischen.