torpedo

n. an explosive device that is set off in an oil well (or a gas well) to start or to increase the flow of oil (or gas) n. a small firework that consists of a percussion cap and some gravel wrapped in paper; explodes when thrown forcefully against a hard surface n. a small explosive device that is placed on a railroad track and fires when a train runs over it; the sound of the explosion warns the engineer of danger ahead n. armament consisting of a long cylindrical self-propelled underwater projectile that detonates on contact with a target