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

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

The U.S. brought in P-8 Poseidon “sub-hunter” aircraft and AC-130J gunships to help with the boarding operation of the ship south of Iceland, according to flight-tracking data and two U.S. officials.

From The Wall Street Journal • Jan. 7, 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

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

I thought Poseidon would deflect it or something, but it landed on the outer comer of the yard and exploded, sending mermen tumbling through the water.

From "The Last Olympian" by Rick Riordan