Where does “errō” come from?

errō (Latin) comes from Proto-Italic erzāō, from Proto-Indo-European h₁ers- — to flow.

Ancestry of “errō”, step by step

Step	Language	Word	Meaning
1	Proto-Italic	erzāō	roam, wander; go astray, waver
2	Proto-Indo-European	h₁ers-	to flow

errō — Etymology, Origin & Word History | Etymology Explorer