Sigismund (variants: Sigmund, Siegmund) is a German proper name, meaning "protection through victory", from Old High German sigu "victory" + munt "hand, protection". Tacitus Latinises it Segimundus. It looks like there is an older form of the High German word "Sieg" (victory): sigis, obviously Gothic and an inferred Germanic form, and there is a younger form: sigi, which is Old Saxon or Old High German sigu (both from about 9th century). A 5th century Prince of Burgundy was known both as Sigismund and Sigimund (see Ernst Förstemann, Altdeutsche Personennamen, 1906; Henning Kaufmann, Altdeutsche Personennamen, Ergänzungsband,1968).
A Lithuanian name Žygimantas, meaning "wealth of (military) campaign", from Lithuanian žygis "campaign, march" + manta "goods, wealth" has been a substitution of the name Sigismund in the Lithuanian language, from which it was adopted by the Ruthenian language as Жыгімонт (such are the cases of Sigismund Kestutaitis, Sigismund Korybut, Sigismund I the Old, Sigismund II Augustus). The Polish spelling is Zygmunt.
Sigismund was the name of several European nobles:
- Saint Sigismund of Burgundy (died 523), King of the Burgundians
- Sigismund of Hungary, Sigismund of Luxembourg (1368–1437), King of Hungary, Holy Roman Emperor and King of Bohemia
- Sigismund Kestutaitis (c.1350–1440), Grand Duke of Lithuania
- Sigismund Korybut (c.1395-c.1435), Lithuanian Duke, participated in Hussite Wars
- Sigismund, Archduke of Austria (1427–1496), ruler of Further Austria
- Archduke Sigismund Francis of Austria (1630-1665), ruler of Further Austria
- Sigismund of Bavaria (1439–1501), a Duke of Bavaria
- Sigismund I the Old (1467–1548), King of Poland, Grand Duke of Lithuania
- Sigismund II Augustus (1520–1572), King of Poland, Grand Duke of Lithuania
- Sigismund III Vasa (1566–1632), King of Sweden (as Sigismund) and Poland, Grand Duke of Lithuania
- Sigismund Báthory (1572–1613), Prince of Transylvania
- Prince Sigismund of Prussia (1864-1866), the fourth child of Friedrich III, German Emperor and Princess Victoria of the United Kingdom
Sigismund/Siegmund may also refer to fictional characters:
- Segismundo, main character of Calderón de la Barca's La vida es sueño.
- Segismundo, 21st century hero of the dramatic novel "United States of Banana" by Giannina Braschi, based on Calderón de la Barca's Life is a Dream.
- Sigismund, a character from the Warhammer 40,000 game series, First Captain of the Imperial Fists Legion and later founder and first High Marshall of the Black Templars Chapter
- Sigismund (bell), a famous bell in the Wawel Cathedral in Kraków, cast in 1520
- Siegmund, a focal character in Richard Wagner's Die Walküre
- Wilhelm Gottsreich Sigismond von Ormstein, Grand Duke of Cassel-Felstein, fictional King of Bohemia in "A Scandal in Bohemia" (Sherlock Holmes adventure)
- Sigismund the mad maths teacher, a character in the Nigel Molesworth school stories