A submerged mine. Obsolete.

American turtle: = torpedo, n. 2. Obsolete.

Originally: a case charged with gunpowder designed to explode under water after a given interval so as to destroy any vessel in its immediate…

A submarine mine. Obsolete. rare.

A type of bomb which detonates when activated by a person, vehicle, etc., passing over or near it; (spec. in early use) such a bomb placed…

a torpedo carried on the end of a pole projecting from the bows of a vessel; = spar torpedo n. at spar, n.1 compounds 2.

a torpedo fixed to the ground or bottom of the sea.

a torpedo fastened on the end of a spar projecting from the bows of the boat.

In naval war: A submarine ‘mine’ sunk in such a position as to explode the enemy's mines by the concussion of its explosion.

an underwater mine designed to be activated by sound waves, esp. those produced by a vessel's propellers.

a submarine mine that is detonated by the approach of a magnetized body such as a ship.

A type of explosive device that is attached magnetically to a ship's hull; so limpet bomb, limpet charge, limpet mine.

a mine actuated by a change in pressure; esp. an underwater mine actuated by the temporary reduction in hydrostatic pressure caused by a passing ship.

A type of unmoored submarine mine detonated magnetically or acoustically as a vessel passes over it. Frequently attributive. Now historical.