Where does “სა- -ო” come from?

სა- -ო (Georgian) comes from Proto-Georgian-Zan *lʿa- -o.

Ancestry of “სა- -ო”, step by step

Step	Language	Word	Meaning
1	Proto-Georgian-Zan	*lʿa- -o	—

სა- -ო — Etymology, Origin & Word History | Etymology Explorer