Poseidon

American  

[poh-sahyd-n, puh-] / poʊˈsaɪd n, pə- /

noun

1. the ancient Greek god of the sea, with the power to cause earthquakes, identified by the Romans with Neptune.

2. Military. a 34-foot (10-meter), submarine-launched U.S. ballistic missile with up to 10 warheads and a range of 2,800 miles (4,502 km).

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Poseidon British  

/ pɒˈsaɪdən /

noun

1. Roman counterpart: Neptune.  Greek myth the god of the sea and of earthquakes; brother of Zeus, Hades, and Hera. He is generally depicted in art wielding a trident

2. a US submarine-launched ballistic missile

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Poseidon Cultural  

1. The Greek name for Neptune, the god in classical mythology who ruled the sea.

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Example Sentences

Yangzijiang plans to acquire a 10% interest in Poseidon, the holding company of Seaspan, one of the world’s largest containership lessors, the analyst notes.

From The Wall Street Journal • Apr. 8, 2026

High above, crews aboard P-8 Poseidon sub-hunting planes—specially modified Boeing 737 jetliners like those Southwest Airlines and Ryanair fly—can peer deep into the sea, launch probes and even fire anti-submarine weapons.

From The Wall Street Journal • Feb. 11, 2026

"All of a sudden it was like Poseidon is having a temper tantrum here with these waves just crashing huge," she added.

From BBC • Dec. 26, 2025

Both the Poseidon and the Burevestnik are second-strike, retaliatory weapons, Mr Galeotti added - and not even the most rabid Kremlin propagandists are suggesting anyone is preparing to launch strikes on Russia.

From BBC • Oct. 31, 2025

Now, being the son of Poseidon and all, I was okay with this.

From "The Last Olympian" by Rick Riordan