Where does “Ποσειδώνας” come from?

Ποσειδώνας (Greek) comes from Ancient Greek Ποσειδῶν, from Latin Posīdōn.

Ancestry of “Ποσειδώνας”, step by step

Step	Language	Word	Meaning
1	Ancient Greek	Ποσειδῶν	Poseidon, god of earthquakes
2	Latin	Posīdōn	—

Ποσειδώνας — Etymology, Origin & Word History | Etymology Explorer