Source : Webster's Revised Unabridged Dictionary (1913)

Horse \Horse\ (h[^o]rs), n. [AS. hors; akin to OS. hros, D. &
   OHG. ros, G. ross, Icel. hross; and perh. to L. currere to
   run, E. course, current Cf. {Walrus}.]
   1. (Zo["o]l.) A hoofed quadruped of the genus {Equus};
      especially, the domestic horse ({E. caballus}), which was
      domesticated in Egypt and Asia at a very early period. It
      has six broad molars, on each side of each jaw, with six
      incisors, and two canine teeth, both above and below. The
      mares usually have the canine teeth rudimentary or
      wanting. The horse differs from the true asses, in having
      a long, flowing mane, and the tail bushy to the base.
      Unlike the asses it has callosities, or chestnuts, on all
      its legs. The horse excels in strength, speed, docility,
      courage, and nobleness of character, and is used for
      drawing, carrying, bearing a rider, and like purposes.

   Note: Many varieties, differing in form, size, color, gait,
         speed, etc., are known, but all are believed to have
         been derived from the same original species. It is
         supposed to have been a native of the plains of Central
         Asia, but the wild species from which it was derived is
         not certainly known. The feral horses of America are
         domestic horses that have run wild; and it is probably
         true that most of those of Asia have a similar origin.
         Some of the true wild Asiatic horses do, however,
         approach the domestic horse in several characteristics.
         Several species of fossil ({Equus}) are known from the
         later Tertiary formations of Europe and America. The
         fossil species of other genera of the family
         {Equid[ae]} are also often called horses, in general
         sense.

   2. The male of the genus horse, in distinction from the
      female or male; usually, a castrated male.