A cigar-shaped, self-propelled underwater projectile launched from a submarine, aircraft, or ship and designed to detonate on contact with or in the vicinity of a target. Any of various submarine explosive devices, especially a submarine mine. A small explosive placed on a railroad track that is fired by the weight of the train to sound a warning of an approaching hazard. An explosive fired in an oil or gas well to begin or increase the flow. A small firework consisting of gravel wrapped in tissue paper with a percussion cap that explodes when thrown against a hard surface. See electric ray. Slang A professional assassin or thug. Chiefly New Jersey See submarine. See Regional Note at submarine. To attack, strike, or sink with a torpedo. To destroy decisively; wreck: torpedo efforts at reform.