Source : Webster's Revised Unabridged Dictionary (1913)

Horse-radish \Horse"-rad`ish\, n. (Bot.)
   A plant of the genus {Nasturtium} ({N. Armoracia}), allied to
   scurvy grass, having a root of a pungent taste, much used,
   when grated, as a condiment and in medicine. --Gray.

   {Horse-radish tree}. (Bot.) See {Moringa}.