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

The U.S. sent a P-8A Poseidon spy plane but elected not to send a destroyer as it had in the past.

From The Wall Street Journal • Mar. 10, 2026

They include Poseidon - a new intercontinental, nuclear armed and nuclear powered undersea autonomous torpedo, and also Burevestnik – a nuclear armed and powered cruise missile.

From BBC • Feb. 4, 2026

Several other US aircraft have flown around the west coast of Scotland and south of Iceland, including a Poseidon reconnaissance plane and a Boeing KC-135T Stratotanker used for refuelling.

From BBC • Jan. 7, 2026

Neither the Poseidon nor the Burevestnik were entirely novel - both had first been presented to the world in 2018 as part of a new array of weapons that Putin called "invincible".

From BBC • Oct. 31, 2025

She was the daughter of King Laomedon, who had cheated Apollo and Poseidon of their wages after at Zeus’s command they had built for the King the walls of Troy.

From "Mythology: Timeless Tales of Gods and Heroes" by Edith Hamilton