Where does “Nereo” come from?

Nereo (Italian) comes from Ancient Greek Νηρεύς — Nereus; the sea-god Nereus.

Ancestry of “Nereo”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Νηρεύς	Nereus; the sea-god Nereus

Nereo — Etymology, Origin & Word History | Etymology Explorer