From Old Norse 'sigr' (victory) and 'mundr' (protector), meaning victorious protector; a hero in Norse saga.
Sigmund is a compound of two ancient Germanic elements: "sigu" or "sig" (victory) and "mund" (protection, guardian), yielding the powerful meaning "victorious protector" or "guardian of victory." The name belongs to the oldest stratum of Germanic heroic nomenclature — the kind of name given to kings and warriors who were expected to embody their name's meaning on the battlefield. It appears across the medieval Germanic world in various spellings: Sigmund in High German, Sigismund in Latinized form, Sigmundr in Old Norse.
In Norse mythology Sigmund is one of the great tragic heroes: son of the god Odin in the guise of an old wanderer, Sigmund is the only mortal able to pull the sword Gramr from the tree Barnstokk, and his saga — recounted in the Völsunga Saga — forms the deep mythological substrate on which Richard Wagner built his Ring Cycle, where the character appears as Siegmund in "Die Walküre." These medieval roots gave the name an enormous literary and musical prestige in the nineteenth century. Its most consequential modern bearer, however, is Sigmund Freud (1856–1939), whose foundational work in psychoanalysis so thoroughly transformed Western thought about the mind that the name carries an almost inescapable intellectual gravity.
In the English-speaking world Sigmund was used primarily in Jewish-German immigrant communities through the late nineteenth and early twentieth centuries, often as a tribute to Freud or to the Germanic naming tradition more broadly. It has since become quite rare in the Anglophone world, sitting in that interesting category of names — Oswald, Aldric, Sigrid — that feel simultaneously archaic, heroic, and a little audacious on a contemporary child. For parents drawn to names with true historical depth, Sigmund is nearly without equal.