Source : Webster's Revised Unabridged Dictionary (1913)

Traction \Trac"tion\, n. [L. trahere, tractum, to draw: cf. F.
   traction.]
   1. The act of drawing, or the state of being drawn; as, the
      traction of a muscle.

   2. Specifically, the act of drawing a body along a plane by
      motive power, as the drawing of a carriage by men or
      horses, the towing of a boat by a tug.

   3. Attraction; a drawing toward. [R.]

   4. The adhesive friction of a wheel on a rail, a rope on a
      pulley, or the like. --Knight.

   {Angle of traction} (Mech.), the angle made with a given
      plane by the line of direction in which a tractive force
      acts.

   {Traction engine}, a locomotive for drawing vehicles on
      highways or in the fields.

Source : WordNet®

traction engine
     n : steam-powered locomotive for drawing heavy loads along
         surfaces other than tracks