Where does “*dū” come from?

*dū (Proto-Celtic) comes from Proto-Indo-European de — Emphatic or contrastive particle, and, but;...

Ancestry of “*dū”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	de	Emphatic or contrastive particle, and, but;...

*dū — Etymology, Origin & Word History | Etymology Explorer