Where does “ratre” come from?

ratre (Tocharian B) comes from Proto-Tocharian *rŭtäre, from Proto-Indo-European h₁rudʰrós, from Proto-Indo-European h₁rewdʰ- — red.

ratre (Tocharian B): red

Definitions

Step	Language	Word	Meaning
1	Proto-Tocharian	*rŭtäre	—
2	Proto-Indo-European	h₁rudʰrós	red
3	Proto-Indo-European	h₁rewdʰ-	red

ratre — Etymology, Origin & Word History | Etymology Explorer