Where does “kr̥s-o-” come from?

kr̥s-o- (Proto-Indo-European) comes from Proto-Indo-European ḱers- — to run.

Ancestry of “kr̥s-o-”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-European	ḱers-	to run

kr̥s-o- — Etymology, Origin & Word History | Etymology Explorer