—n. 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.
—adj. 1. situated, occurring, operating, or living under the surface of the sea: a submarine mountain. 2. of, pertaining to, or carried on by a submarine or submarines: submarine warfare.
—v.i. 1. to participate in the operating of a submarine.
2. to move or slide under something.
3. Slang. a. to be thrown under the steering wheel of the vehicle one is driving during a frontal crash.
b. to be thrown out of one's seat belt in such a crash.