Source : Webster's Revised Unabridged Dictionary (1913)

Submarine \Sub`ma*rine"\, n.
   A submarine boat; esp., Nav., a submarine torpedo boat; --
   called specif. {submergible submarine} when capable of
   operating at various depths and of traveling considerable
   distances under water, and {submersible submarine} when
   capable of being only partly submerged, i.e., so that the
   conning tower, etc., is still above water. The latter type
   and most of the former type are submerged as desired by
   regulating the amount of water admitted to the ballast tanks
   and sink on an even keel; some of the former type effect
   submersion while under way by means of horizontal rudders, in
   some cases also with admission of water to the ballast tanks.