Gudrun combines the Old Norse guðr (battle) and rún (secret, rune) — meaning "secret battle." In the Volsung Saga and Nibelungenlied, Gudrun (Kriemhild in German) is the wife of Sigurd, mother of Aslaug.
Gudrun is widely used in modern Scandinavia and Iceland.
Gudrun is a compound name. Its parts are guð + rún — each an attested element with a recorded meaning of its own.
Gudrun does not currently appear in the US Social Security Administration's top 1,000 girls' names, so we don't publish a US rank or birth count for it. That says nothing about the name's standing elsewhere in the world — only that it sits outside the ranked US data we rely on.
In Pythagorean numerology the letters of Gudrun reduce to 4, The Builder. This is a traditional interpretive system, not a factual claim about the name.