submarine

American  

[suhb-muh-reen, suhb-muh-reen, suhb-muh-reen] / ˌsʌb məˈrin, ˈsʌb məˌrin, ˌsʌb məˈrin /

noun

1. a vessel that can be submerged and navigated under water, usually built for warfare and armed with torpedoes or guided missiles.

2. something situated or living under the surface of the sea, as a plant or animal.

3. Chiefly Northeastern and North Midland U.S. a hero sandwich.

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adjective

1. situated, occurring, operating, or living under the surface of the sea.

   a submarine mountain.

2. of, relating to, or carried on by a submarine or submarines.

   submarine warfare.

verb (used without object)

submarined, submarining

1. to participate in the operating of a submarine.

2. to move or slide under something.

3. Slang.

   1. to be thrown under the steering wheel of the vehicle one is driving during a frontal crash.

   2. to be thrown out of one's seat belt in such a crash.

verb (used with object)

submarined, submarining

1. to attack or sink by submarine.

submarine British  

/ ˈsʌbməˌriːn, ˌsʌbməˈriːn /

noun

1. Often shortened to: sub.  a vessel, esp one designed for warfare, capable of operating for protracted periods below the surface of the sea

2. (modifier)

   1. of or relating to a submarine

      a submarine captain

   2. occurring or situated below the surface of the sea

      a submarine cable

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Regionalisms

See hero sandwich.

Other Word Forms

• antisubmarine adjective

Etymology

Origin of submarine

1640–50; 1895–1900 submarine for def. 1; sub- + marine

Explanation

If you're in the Navy, a submarine is a military ship that goes under the water. If you're hungry, it's a type of sandwich. This word mainly refers to a vessel that travels underwater and is armed with torpedoes — also known as a U-boat. But you can submarine someone by attacking them with a submarine or bringing them down with a blow to the legs. A disappointment can submarine — or sink — your hopes and dreams. In the kitchen, a submarine is what you call a long, crusty sandwich filled with meats and cheese — also known as a sub, grinder, hero, or hoagie.

Example Sentences

SYDNEY—From the Baltic Sea to the Pacific Ocean, a global scramble is under way to protect submarine cables vulnerable to potential sabotage.

From The Wall Street Journal • Apr. 9, 2026

New technologies like distributed acoustic sensing and Seabed Sentry are being developed to monitor and protect vulnerable submarine cables.

From The Wall Street Journal • Apr. 9, 2026

Last year, German defence tech firm Helsing opened a factory on the city's outskirts, creating 50 jobs producing unmanned submarine gliders.

From BBC • Apr. 8, 2026

Just the year before, in February 1942, a Japanese submarine had shelled an oil field near Santa Barbara, and the very next night, L.A. was ordered into a blackout.

From Los Angeles Times • Mar. 26, 2026

The tracking stations captured the signals with their sixty-four-foot receiving dishes, then relayed this data plus voice communications through a jumble of submarine cables, landlines, and radio waves to the computer center at Goddard.

From "Hidden Figures" by Margot Lee Shetterly

Related Words

• sub
• torpedo