Source : Webster's Revised Unabridged Dictionary (1913)

Draft \Draft\, a.
   1. Pertaining to, or used for, drawing or pulling (as
      vehicles, loads, etc.). Same as {Draught}.

   2. Relating to, or characterized by, a draft, or current of
      air. Same as {Draught}.

   Note: The forms draft and draught, in the senses above-given,
         are both on approved use.

   {Draft box}, {Draft engine}, {Draft horse}, {Draft net},
   {Draft ox}, {Draft tube}. Same as {Draught box}, {Draught
      engine}, etc. See under {Draught}.

Source : WordNet®

draft horse
     n : horse adapted for drawing heavy loads [syn: {draught horse},
          {dray horse}]