Where does “Εὐρύαλος” come from?

Εὐρύαλος (Ancient Greek) comes from Ancient Greek εὐρύς, from Proto-Hellenic *eurús.

Ancestry of “Εὐρύαλος”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	εὐρύς	wide, broad, spacious, especially of heaven,...
2	Proto-Hellenic	*eurús	—

Εὐρύαλος — Etymology, Origin & Word History | Etymology Explorer