Source : Webster's Revised Unabridged Dictionary (1913)

Horseshoe \Horse"shoe`\, n.
   1. A shoe for horses, consisting of a narrow plate of iron in
      form somewhat like the letter U, nailed to a horse's hoof.

   2. Anything shaped like a horsehoe crab.

   3. (Zo["o]l.) The Limulus of horsehoe crab.

   {Horsehoe head} (Med.), an old name for the condition of the
      skull in children, in which the sutures are too open, the
      coronal suture presenting the form of a horsehoe.
      --Dunglison.

   {Horsehoe magnet}, an artificial magnet in the form of a
      horsehoe.

   {Horsehoe nail}. See {Horsenail}.

   {Horsehoe nose} (Zo["o]l.), a bat of the genus {Rhinolophus},
      having a nasal fold of skin shaped like a horsehoe.