Source : Webster's Revised Unabridged Dictionary (1913)

Midshipman \Mid"ship`man\, n.; pl. {Midshipmen}.
   1.
      (a) Formerly, a kind of naval cadet, in a ship of war,
          whose business was to carry orders, messages, reports,
          etc., between the officers of the quarter-deck and
          those of the forecastle, and render other services as
          required.
      (b) In the English naval service, the second rank attained
          by a combatant officer after a term of service as
          naval cadet. Having served three and a half years in
          this rank, and passed an examination, he is eligible
          to promotion to the rank of lieutenant.
      (c) In the United States navy, the lowest grade of
          officers in line of promotion, being graduates of the
          Naval Academy awaiting promotion to the rank of
          ensign.

   2. (Zo["o]l.) An American marine fish of the genus
      {Porichthys}, allied to the toadfish.

   {Cadet midshipman}, formerly a title distinguishing a cadet
      line officer from a cadet engineer at the U. S. Naval
      Academy. See under {Cadet}.

   {Cadet midshipman}, formerly, a naval cadet who had served
      his time, passed his examinations, and was awaiting
      promotion; -- now called, in the United States,
      {midshipman}; in England, {sublieutenant}.