The Collaborative International Dictionary of English v.0.48:

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.
      [1913 Webster]

   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.
      [1913 Webster]

   3. Attraction; a drawing toward. [R.]
      [1913 Webster]

   4. The adhesive friction of a wheel on a rail, a rope on a
      pulley, or the like; as, the car is stuck in the snow
      because it can;t get any traction. --Knight.
      [1913 Webster +PJC]

   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.
      [1913 Webster]

WordNet (r) 3.0 (2006):

traction
    n 1: the friction between a body and the surface on which it
         moves (as between an automobile tire and the road) [syn:
         grip, traction, adhesive friction]
    2: (orthopedics) the act of pulling on a bone or limb (as in a
       fracture) to relieve pressure or align parts in a special way
       during healing; "his leg was in traction for several days"

Moby Thesaurus II by Grady Ward, 1.0:

42 Moby Thesaurus words for "traction":
   adduction, adhesion, advantage, affinity, allurement, attractance,
   attraction, attractiveness, attractivity, capillarity,
   capillary attraction, centripetal force, draft, drag, draw,
   drawing, drayage, extraction, foothold, footing, friction,
   gravitation, gravity, grip, haulage, hauling, heaving, hold,
   magnetism, mutual attraction, pull, pulling, pulling power,
   purchase, sympathy, toehold, towage, towing, tractive power, tug,
   tug-of-war, tugging