dray horse

from WordNet (r) 3.0 (2006)

dray 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

Dray \Dray\, n. [AS. dr[ae]ge a dragnet, fr. dragan. ????. See
   {Draw}, and cf. 2d {Drag}, 1st {Dredge}.]
   1. A strong low cart or carriage used for heavy burdens.
      --Addison.
      [1913 Webster]

   2. A kind of sledge or sled. --Halliwell.
      [1913 Webster]

   {Dray cart}, a dray.

   {Dray horse}, a heavy, strong horse used in drawing a dray.
      [1913 Webster]