Where does “ruo” come from?

ruo (Latin) comes from Proto-Indo-European h₃rew-, from Proto-Indo-European -w-.

Ancestry of “ruo”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	h₃rew-	to run, to hurry
2	Proto-Indo-European	-w-	—

ruo — Etymology, Origin & Word History | Etymology Explorer