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

New Zealand scrambled P-8A Poseidon surveillance aircraft and naval assets to monitor the maneuvers, which demonstrated China’s increasing ability to deploy forces farther afield.

From The Wall Street Journal • Mar. 25, 2026

"Regarding the tests of Poseidon and Burevestnik, we hope that the information was conveyed correctly to President Trump," Kremlin spokesman Dmitry Peskov told journalists, referencing the names of Russian weapons.

From BBC • Nov. 3, 2025

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

Since August, the Pentagon has deployed three guided-missile destroyers, F-35B jet fighters, MQ-9 Reaper drones, P-8 Poseidon spy planes, assault ships and a secretive special-operations ship.

From The Wall Street Journal • Oct. 14, 2025

The seat of Poseidon stood just to the right of Zeus’s, but it wasn’t nearly as grand.

From "The Last Olympian" by Rick Riordan