An Etymological Dictionary of the German Language/Annotated/Mund
Mund (1.), masculine, ‘mouth,’ from Middle High German munt, Old High German mund, masculine, ‘mouth, outlet,’ Old Saxon mûð, masculine, Dutch mond, ‘mouth,’ Anglo-Saxon mûð, masculine, English mouth, Old Icelandic munnr, muðr, Gothic munþs, masculine, ‘mouth.’ The common Teutonic word munþa-z, masculine, may be based on pre-Teutonic mńto-s and connected with Latin mentum, ‘chin’ (of men and beasts). In the non-Teutonic languages also evidence of the kinship of Mund and Maul may be found, since the latter is an old *mû-lo-, while the former may represent *mu-nþo (with a participle suffix, see Zahn). Compare Sanscrit mú-kha, ‘mouth.’
Mund (2.), feminine, ‘protection,’ from Middle High German and Old High German munt, feminine, ‘protection, hand’; compare Anglo-Saxon mund, ‘hand, protection,’ Old Icelandic mund, feminine, ‘hand’; the Dutch term still exists in mond-baar with the variant momber, ‘guardian,’ Old Saxon mundboro, Anglo-Saxon mundbora, Old High German muntboro, Middle High German muntbor, masculine, ‘protector, tutor’; compare also Vormund and Mündel. Mund is certainly not connected with Latin mûnire (with regard to û from Aryan ai, compare moenia), but is probably derived from a root cognate with that of Latin manus, ‘hand.’