Where does “Եսայի” come from?

Եսայի (Old Armenian) comes from Ancient Greek Ἠσαΐας, from Hebrew יְשַׁעְיָהוּ.

Ancestry of “Եսայի”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Ἠσαΐας	—
2	Hebrew	יְשַׁעְיָהוּ	—

Եսայի — Etymology, Origin & Word History | Etymology Explorer