Situated or living under or in the sea, either at the bottom or below the surface; below the surface of the sea: as, submarine plants; a submarine telegraph.
Occurring or carried on below the surface of the sea: as, submarine explorations; designed for use under the sea: as, submarine armor.
A submarine plant.
noun.
A vessel designed to navigate either entirely under water or on the surface, with a crew contained within it and with its own motive power; specifically, a submarine torpedo-boat.