Source : Webster's Revised Unabridged Dictionary (1913)

Vehicle \Ve"hi*cle\, n. [L. vehiculum, fr. vehere to carry; akin
   to E. way, wain. See {Way}, n., and cf. {Convex}, {Inveigh},
   {Veil}, {Vex}.]
   1. That in or on which any person or thing is, or may be,
      carried, as a coach, carriage, wagon, cart, car, sleigh,
      bicycle, etc.; a means of conveyance; specifically, a
      means of conveyance upon land.

   2. That which is used as the instrument of conveyance or
      communication; as, matter is the vehicle of energy.

            A simple style forms the best vehicle of thought to
            a popular assembly.                   --Wirt.

   3. (Pharm.) A substance in which medicine is taken.

   4. (Paint.) Any liquid with which a pigment is applied,
      including whatever gum, wax, or glutinous or adhesive
      substance is combined with it.

   Note: Water is used in fresco and in water-color painting,
         the colors being consolidated with gum arabic; size is
         used in distemper painting. In oil painting, the fixed
         oils of linseed, nut, and poppy, are used; in
         encaustic, wax is the vehicle. --Fairholt.

Vehicle \Ve"hi*cle\, n. (Chem.)
   A liquid used to spread sensitive salts upon glass and paper
   for use in photography.

Source : WordNet®

vehicle
     n 1: a conveyance that transports people or objects
     2: a medium for the expression or achievement of something;
        "his editorials provided a vehicle for his political
        views"; "a congregation is a vehicle of group identity"
     3: any inanimate object (as a towel or money or clothing or
        dishes or books or toys etc.) that can transmit infectious
        agents from one person to another [syn: {fomite}]