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

These latest interceptions come amid increased Russian aggression in the region, the MoD added, pointing to recent submarine activity over critical underwater British infrastructure in the North Sea.

From BBC • May 20, 2026

Visitors also encountered early examples of X-ray machines, infant incubators, automobiles, early “flying machines” and submarine technology.

From The Wall Street Journal • May 16, 2026

The discovery comes from a Curtin University-led study that explored the Cape Range and Cloates submarine canyons, located about 1200 kilometers north of Perth.

From Science Daily • May 14, 2026

Another German ship and submarine maker, Thyssenkrupp Marine Systems, had itself made a competing offer for German Naval Yards in January.

From Barron's • May 7, 2026

Soon afterward, a US submarine determined that the pod had gone missing.

From "Spies: The Secret Showdown Between America and Russia" by Marc Favreau

Related Words

• sub
• torpedo