Source : Webster's Revised Unabridged Dictionary (1913)

Car \Car\, n. [OF. car, char, F. cahr, fr. L. carrus, Wagon: a
   Celtic word; cf. W. car, Armor. karr, Ir. & Gael. carr. cf.
   {Chariot}.]
   1. A small vehicle moved on wheels; usually, one having but
      two wheels and drawn by one horse; a cart.

   2. A vehicle adapted to the rails of a railroad. [U. S.]

   Note: In England a railroad passenger car is called a railway
         carriage; a freight car a goods wagon; a platform car a
         goods truck; a baggage car a van. But styles of car
         introduced into England from America are called cars;
         as, tram car. Pullman car. See {Train}.

   3. A chariot of war or of triumph; a vehicle of splendor,
      dignity, or solemnity. [Poetic].

            The gilded car of day.                --Milton.

            The towering car, the sable steeds.   --Tennyson.

   4. (Astron.) The stars also called Charles's Wain, the Great
      Bear, or the Dipper.

            The Pleiads, Hyads, and the Northern Car. --Dryden.

   5. The cage of a lift or elevator.

   6. The basket, box, or cage suspended from a balloon to
      contain passengers, ballast, etc.

   7. A floating perforated box for living fish. [U. S.]

   {Car coupling}, or {Car coupler}, a shackle or other device
      for connecting the cars in a railway train. [U. S.]

   {Dummy car} (Railroad), a car containing its own steam power
      or locomotive.

   {Freight car} (Railrood), a car for the transportation of
      merchandise or other goods. [U. S.]

   {Hand car} (Railroad), a small car propelled by hand, used by
      railroad laborers, etc. [U. S.]

   {Horse car}, or {Street car}, an omnibus car, draw by horses
      or other power upon rails laid in the streets. [U. S.]

   {Palace car}, {Drawing-room car}, {Sleeping car}, {Parlor
   car}, etc. (Railroad), cars especially designed and furnished
      for the comfort of travelers.

Freight \Freight\, a.
   Employed in the transportation of freight; having to do with
   freight; as, a freight car.

   {Freight agent}, a person employed by a transportation
      company to receive, forward, or deliver goods.

   {Freight car}. See under {Car}.

   {Freight train}, a railroad train made up of freight cars; --
      called in England goods train.

Source : WordNet®

freight car
     n : a railway car that carries freight