Where does “upa-” come from?

upa- (Proto-Indo-Aryan) comes from Proto-Indo-Iranian upa-, from Proto-Indo-European upo — under, up from under; up from under, over; up,...

Ancestry of “upa-”, step by step

Step	Language	Word	Meaning
1	Proto-Indo-Iranian	upa-	towards
2	Proto-Indo-European	upo	under, up from under; up from under, over; up,...

upa- — Etymology, Origin & Word History | Etymology Explorer