An Etymological Dictionary of the German Language/Zwerch-

by Friedrich Kluge

Zwerch-, ‘athwart, across,’ in compounds such as Zwerchfell, ‘diaphragm,’ Zwerchpfeife, ‘life,’ Zwerchsack, ‘knapsack, wallet,’ from MidHG. twërch, dwërch (also quërch), adj., ‘oblique, reversed, athwart,’ HG. dwërah, twërh, ‘oblique, athwart.’ Corresponding to AS. þweorh, ‘perverse,’ Goth. þwaírhs, ‘angry’ (þwaírhei, f., ‘anger, dispute’), Du. dwars, Dan. tvœrs, tvœrt, ‘athwart.’ With these is also connected ModHG. überzwerch, adj. and adv., ‘across, athwart, crosswise’ (MidHG. über twërch, über zwërch). The same Aryan root tverk appears also perhaps in AS. þurh, ‘through’ (see durch). Beside twërh, the MidHG. and OHG. variant twër, ‘oblique, athwart,’ occurs (in MidHG. also quër; see quer), OIc. þverr, ‘athwart, impeding.’ Teut. þwerhwo- points to an Aryan root twerk, with which Lat. torqueo is connected.