Source : Webster's Revised Unabridged Dictionary (1913)

Barbed \Barbed\, a.
   Furnished with a barb or barbs; as, a barbed arrow; barbed
   wire.

   {Barbed wire}, a wire, or a strand of twisted wires, armed
      with barbs or sharp points. It is used for fences.

Source : WordNet®

barbed wire
     n : strong wire with barbs at regular intervals used to prevent
         passage