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

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

"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

Flights of B1 bombers and P-8 Poseidon spy planes have also been visible on plane tracking platforms.

From BBC • Oct. 23, 2025

Since August, the U.S. has deployed B-52 bomber aircraft, F-35B jet fighters, P-8 Poseidon spy planes, eight warships and a special-operations vessel to the region, among other weaponry.

From The Wall Street Journal • Oct. 17, 2025

The seventh labor was to go to Crete and fetch from there the beautiful savage bull that Poseidon had given Minos.

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