Where does “Мецамор” come from?

Мецамор (Russian) comes from Armenian Մեծամոր, from Old Armenian Մեծամօր, from Old Armenian մեծ, from Old Armenian ան-, from Proto-Indo-European n̥-, from Proto-Indo-European ne — not.

Ancestry of “Мецамор”, step by step

Step	Language	Word	Meaning
1	Armenian	Մեծամոր	Metsamor river
2	Old Armenian	Մեծամօր	—
3	Old Armenian	մեծ	great; large, big; strong, powerful, mighty;...
4	Old Armenian	ան-	a privative prefix, without, -less, un-, dis-;...
5	Proto-Indo-European	n̥-	not, un-
6	Proto-Indo-European	ne	not

Every word from Proto-Indo-European ne →Every word from Proto-Indo-European n̥- →Every word from Old Armenian ան- →