Draft horse

from WordNet (r) 3.0 (2006)

draft horse
    n 1: horse adapted for drawing heavy loads [syn: {draft horse},
         {draught horse}, {dray horse}]

from The Collaborative International Dictionary of English v.0.48

Draft \Draft\, a.
   1. Pertaining to, or used for, drawing or pulling (as
      vehicles, loads, etc.). Same as {Draught}; as, a draft
      horse.
      [1913 Webster]

   2. Relating to, or characterized by, a draft, or current of
      air. Same as {Draught}.
      [1913 Webster]

   Note: The forms draft and draught, in the senses above-given,
         are both in approved use.
         [1913 Webster]

   {Draft box}, {Draft engine}, {Draft horse}, {Draft net},
   {Draft ox}, {Draft tube}. Same as {Draught box}, {Draught
      engine}, etc. See under {Draught}.
      [1913 Webster]