Where does “(j)edьnъ” come from?

(j)edьnъ (Proto-Slavic) comes from Proto-Indo-European óynos — one; single.

Ancestry of “(j)edьnъ”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	óynos	one; single

(j)edьnъ — Etymology, Origin & Word History | Etymology Explorer