Quick answer
Walburga is a girl name meaning "power of the fortress".
Meaning and history
The name means "power of the fortress" from Old German walt meaning "power, authority" and burg meaning "fortress" (or perhaps from Old English cognates, though as an Old English name it is unattested). This was the name of an 8th-century Anglo-Saxon saint who did missionary work in Germany.
Notes and context
Usage: german