Source : Webster's Revised Unabridged Dictionary (1913)

Sway bar \Sway bar\ (Vehicles)
   (a) A bar attached to the hounds, in the rear of the front
       axle, so as to slide on the reach as the axle is swung in
       turning the vehicle.
   (b) Either of the two bars used in coupling the front and
       rear sleds of a logging sled; also, the bar used to
       couple two logging cars.