The Collaborative International Dictionary of English v.0.48:

Homing \Hom"ing\ (h[=o]m"[i^]ng), p. a.
   Home-returning; -- used specifically of carrier pigeons.
   [1913 Webster]

   Homing pigeon, any pigeon trained to return home from a
      distance. Also called carrier pigeon. Most are bred from
      the domestic pigeon Columba livia. Homing pigeons are
      used for sending back messages or for flying races. By
      carrying the birds away and releasing them at gradually
      increasing distances from home, they may be trained to
      return with more or less certainty and promptness from
      distances up to four or five hundred miles. The birds
      typically do not stop on their way home, and may average
      as much as 60 miles per hour on their return trip. If the
      distance is increased much beyond 400 miles, the birds are
      unable to cover it without stopping for a prolonged rest,
      and their return becomes doubtful. The record for returnig
      from a distance is close to 1,200 miles. Homing pigeons
      are not bred for fancy points or special colors, but for
      strength, speed, endurance, and intelligence or homing
      instinct. Although used since ancient times, homing
      pigeons have been largely displaced for practical purposes
      by radio and electronic communications, but they are still
      used in some special situations at the end of the 20th
      century. They were used in military operations as recently
      as in World War II.
      [Webster 1913 Suppl. +PJC] hominian

The Collaborative International Dictionary of English v.0.48:

Carrier \Car"ri*er\, n. [From Carry.]
   1. One who, or that which, carries or conveys; a messenger.
      [1913 Webster]

            The air which is but . . . a carrier of the sounds.
                                                  --Bacon.
      [1913 Webster]

   2. One who is employed, or makes it his business, to carry
      goods for others for hire; a porter; a teamster.
      [1913 Webster]

            The roads are crowded with carriers, laden with rich
            manufactures.                         --Swift.
      [1913 Webster]

   3. (Mach.) That which drives or carries; as:
      (a) A piece which communicates to an object in a lathe the
          motion of the face plate; a lathe dog.
      (b) A spool holder or bobbin holder in a braiding machine.
          (c) A movable piece in magazine guns which transfers
          the cartridge to a position from which it can be
          thrust into the barrel.
          [1913 Webster]

   Carrier pigeon (Zool.), a variety of the domestic pigeon
      used to convey letters from a distant point to to its
      home.

   Carrier shell (Zool.), a univalve shell of the genus
      Phorus; -- so called because it fastens bits of stones
      and broken shells to its own shell, to such an extent as
      almost to conceal it.

   Common carrier (Law.) See under Common, a.
      [1913 Webster]

WordNet (r) 3.0 (2006):

carrier pigeon
    n 1: a homing pigeon used to carry messages

Moby Thesaurus II by Grady Ward, 1.0:

53 Moby Thesaurus words for "carrier pigeon":
   Aquarius, Ganymede, Hebe, bearer, bheesty, busboy, caddie,
   cargo handler, carrier, carter, common carrier, conveyer, coolie,
   cupbearer, drayman, express, expressman, freighter, gun bearer,
   hauler, homer, homing pigeon, letter carrier, litter-bearer,
   mail car, mail coach, mail packet, mail train, mail truck, mailer,
   mailplane, packet boat, pigeon post, porter, post boat, post car,
   post coach, post-horse, post-office car, poster, railway mail car,
   redcap, shield-bearer, skycap, stevedore, stretcher-bearer,
   the Water Bearer, transporter, truck driver, trucker, wagoner,
   water boy, water carrier