Where does “Արաքս” come from?

Արաքս (Armenian) comes from Ancient Greek Ἀράξης, from Old Median Araxs(ā).

Ancestry of “Արաքս”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Ἀράξης	—
2	Old Median	Araxs(ā)	—

Արաքս — Etymology, Origin & Word History | Etymology Explorer