Where does “rubeō” come from?

rubeō (Latin) comes from Proto-Italic ruðēō, from Proto-Indo-European h₁rudʰéh₁ti, from Proto-Indo-European h₁rewdʰ- — red.

Ancestry of “rubeō”, step by step

Step	Language	Word	Meaning
1	Proto-Italic	ruðēō	—
2	Proto-Indo-European	h₁rudʰéh₁ti	to be red
3	Proto-Indo-European	h₁rewdʰ-	red

rubeō — Etymology, Origin & Word History | Etymology Explorer