An Etymological Dictionary of the German Language/Annotated/Zwerch-

by Friedrich Kluge

Zwerch-, ‘athwart, across,’ in compounds such as Zwerchfell, ‘diaphragm,’ Zwerchpfeife, ‘life,’ Zwerchsack, ‘knapsack, wallet,’ from Middle High German twërch, dwërch (also quërch), adjective, ‘oblique, reversed, athwart,’ High German dwërah, twërh, ‘oblique, athwart.’ Corresponding to Anglo-Saxon þweorh, ‘perverse,’ Gothic þwaírhs, ‘angry’ (þwaírhei, feminine, ‘anger, dispute’), Dutch dwars, Danish tvœrs, tvœrt, ‘athwart.’ With these is also connected Modern High German überzwerch, adjective and adverb, ‘across, athwart, crosswise’ (Middle High German über twërch, über zwërch). The same Aryan root tverk appears also perhaps in Anglo-Saxon þurh, ‘through’ (see durch). Beside twërh, the Middle High German and Old High German variant twër, ‘oblique, athwart,’ occurs (in Middle High German also quër; see quer), Old Icelandic þverr, ‘athwart, impeding.’ Teutonic þwerhwo- points to an Aryan root twerk, with which Latin torqueo is connected.