Where does “милъ” come from?

милъ (Old East Slavic) comes from Proto-Slavic milъ, from Proto-Balto-Slavic meiʔlos, from Proto-Indo-European meyl-.

милъ (Old East Slavic): dear, sweet

Definitions

Step	Language	Word	Meaning
1	Proto-Slavic	milъ	dear, nice, gentle, mild, soft, pleasant, polite
2	Proto-Balto-Slavic	meiʔlos	—
3	Proto-Indo-European	meyl-	—

милъ — Etymology, Origin & Word History | Etymology Explorer