Where does “vъ(n)-” come from?

vъ(n)- (Proto-Slavic) comes from Proto-Indo-European h₁én — in.

Ancestry of “vъ(n)-”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	h₁én	in

Words derived from “vъ(n)-”

Every word from Proto-Indo-European h₁én →

vъ(n)- — Etymology, Origin & Word History | Etymology Explorer