Where does “roudos” come from?

roudos (Proto-Balto-Slavic) comes from Proto-Indo-European h₁rowdʰ-o-, from Proto-Indo-European h₁rewdʰ- — red.

Ancestry of “roudos”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	h₁rowdʰ-o-	—
2	Proto-Indo-European	h₁rewdʰ-	red

roudos — Etymology, Origin & Word History | Etymology Explorer