Source : Webster's Revised Unabridged Dictionary (1913)

Pilot \Pi"lot\, n. [F. pilote, prob. from D. peillood plummet,
   sounding lead; peilen, pegelen, to sound, measure (fr. D. &
   G. peil, pegel, a sort of measure, water mark) + lood lead,
   akin to E. lead. The pilot, then, is the lead man, i. e., he
   who throws the lead. See {Pail}, and {Lead} a metal.]
   1. (Naut.) One employed to steer a vessel; a helmsman; a
      steersman. --Dryden.

   2. Specifically, a person duly qualified, and licensed by
      authority, to conduct vessels into and out of a port, or
      in certain waters, for a fixed rate of fees.

   3. Figuratively: A guide; a director of another through a
      difficult or unknown course.

   4. An instrument for detecting the compass error.

   5. The cowcatcher of a locomotive. [U.S.]

   {Pilot balloon}, a small balloon sent up in advance of a
      large one, to show the direction and force of the wind.

   {Pilot bird}. (Zo["o]l.)
      (a) A bird found near the Caribbee Islands; -- so called
          because its presence indicates to mariners their
          approach to these islands. --Crabb.
      (b) The black-bellied plover. [Local, U.S.]

   {Pilot boat}, a strong, fast-sailing boat used to carry and
      receive pilots as they board and leave vessels.

   {Pilot bread}, ship biscuit.

   {Pilot cloth}, a coarse, stout kind of cloth for overcoats.
      

   {Pilot engine}, a locomotive going in advance of a train to
      make sure that the way is clear.

   {Pilot fish}. (Zo["o]l)
      (a) A pelagic carangoid fish ({Naucrates ductor}); -- so
          named because it is often seen in company with a
          shark, swimming near a ship, on account of which
          sailors imagine that it acts as a pilot to the shark.
      (b) The rudder fish ({Seriola zonata}).

   {Pilot jack}, a flag or signal hoisted by a vessel for a
      pilot.

   {Pilot jacket}, a pea jacket.

   {Pilot nut} (Bridge Building), a conical nut applied
      temporarily to the threaded end of a pin, to protect the
      thread and guide the pin when it is driven into a hole.
      --Waddell.

   {Pilot snake} (Zo["o]l.)
      (a) A large North American snake ({Coluber obsoleus}). It
          is lustrous black, with white edges to some of the
          scales. Called also {mountain black snake}.
      (b) The pine snake.

   {Pilot whale}. (Zo["o]l.) Same as {Blackfish}, 1.

Source : WordNet®

Naucrates ductor
     n : small pelagic fish often accompanying sharks or mantas [syn:
          {pilotfish}]