Where does “gebursdag” come from?

gebursdag (Norwegian Nynorsk) comes from German Geburtstag, from Middle High German geburttac, from Old High German giburtitag.

gebursdag (Norwegian Nynorsk): a birthday

Definitions

Step	Language	Word	Meaning
1	German	Geburtstag	birthday
2	Middle High German	geburttac	—
3	Old High German	giburtitag	—

gebursdag — Etymology, Origin & Word History | Etymology Explorer