Where does “dyrker” come from?

dyrker (Norwegian Bokmål) comes from Norwegian Bokmål dyrke, from Old Norse dýrka, from Old Norse dýrr, from Proto-Germanic *durz, from Proto-Indo-European dʰwṓr, from Proto-Indo-European dʰwer- — door.

dyrker (Norwegian Bokmål): grower, cultivator

Definitions

grower, cultivator

Ancestry of “dyrker”, step by step

Step	Language	Word	Meaning
1	Norwegian Bokmål	dyrke	to engage in; to study; to cultivate, till
2	Old Norse	dýrka	—
3	Old Norse	dýrr	dear, valuable
4	Proto-Germanic	*durz	—
5	Proto-Indo-European	dʰwṓr	door
6	Proto-Indo-European	dʰwer-	door

Every word from Proto-Indo-European dʰwer- →Every word from Proto-Indo-European dʰwṓr →Every word from Proto-Germanic *durz →