Quick answer
Poseidon is a boy name.
Pronunciation: Classical Greek /po.seː.dɔ̂ːn/; English /pə.ˈsaɪ.dn̩/.
Meaning and history
Possibly derived from Greek πόσις ( posis ) meaning "husband, lord" and δᾶ ( da ) meaning "earth". The name first appears in Mycenaean Greek inscriptions as po-se-da-o. In Greek mythology Poseidon was the unruly god of the sea and earthquakes, the brother of Zeus. He was often depicted carrying a trident and riding in a chariot drawn by white horses.
Notes and context
Usage: greek mythology | Ancient Greek: Ποσειδῶν