Where does “dênu” come from?

dênu (Proto-Celtic) comes from Proto-Indo-European dʰeh₁- — to do, put, place.

Ancestry of “dênu”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	dʰeh₁-	to do, put, place

dênu — Etymology, Origin & Word History | Etymology Explorer