Source : Webster's Revised Unabridged Dictionary (1913)

Ash \Ash\ ([a^]sh), n. [OE. asch, esh, AS. [ae]sc; akin to OHG.
   asc, Sw. & Dan. ask, Icel. askr, D. esch, G. esche.]
   1. (Bot.) A genus of trees of the Olive family, having
      opposite pinnate leaves, many of the species furnishing
      valuable timber, as the European ash ({Fraxinus
      excelsior}) and the white ash ({F. Americana}).

   {Prickly ash} ({Zanthoxylum Americanum}) and {Poison ash}
      ({Rhus venenata}) are shrubs of different families,
      somewhat resembling the true ashes in their foliage.

   {Mountain ash}. See {Roman tree}, and under {Mountain}.

   2. The tough, elastic wood of the ash tree.

   Note: Ash is used adjectively, or as the first part of a
         compound term; as, ash bud, ash wood, ash tree, etc.

Source : WordNet®

Zanthoxylum americanum
     n : small deciduous aromatic shrub (or tree) having spiny
         branches and yellowish flowers; eastern North America
         [syn: {toothache tree}, {sea ash}, {Zanthoxylum fraxineum}]