Where does “մեյն-” come from?

մեյն- (Old Armenian) comes from Old Armenian միայն, from Old Armenian այն, from Old Armenian նո-, from Proto-Indo-European h₁nós.

Ancestry of “մեյն-”, step by step

Step	Language	Word	Meaning
1	Old Armenian	միայն	only, sole, singular; alone, lonely; simple,...
2	Old Armenian	այն	that
3	Old Armenian	նո-	that
4	Proto-Indo-European	h₁nós	—

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