(hydrology, oceanology) A river-like current on the seabed.

Existing, relating to, or made for use beneath the sea. / Hidden or undisclosed. / (baseball) Of a pitch, thrown with the hand lower than the elbow.

A boat that can go underwater. / A kind of sandwich made in a long loaf of bread. / (baseball) Pitch delivered with an underhand motion. / Any submarine plant or animal.

(intransitive) To operate or serve on a submarine. / (transitive) To torpedo; to destroy with a sudden sneak attack. / (intransitive, sometimes figuratively) To sink or submerge oneself.

Pertaining to the fatty layer under the skin.

The matter or thought presented for consideration in some statement or discussion; that which is made the object of thought or study.

A large landmass which is either smaller than a continent (such as Greenland), or part of an even larger continent (such as the Indian subcontinent).

The Indian subcontinent, South Asia.

Able to be submerged.

(Britain) A small nonmilitary, non-nuclear submarine for exploration. / (Britain) A retroactive term used for non-nuclear submarines; nuclear submarines are termed "true submarines".