xanthoxylum \xanthox"ylum\, n. nl., from gr. xanqo`s yellow +
   xy`lon wood. bot.
   a genus of prickly shrubs or small trees, the bark and rots
   of which are of a deep yellow color; prickly ash.
   1913 webster

   note: the commonest species in the northern united states is
         xanthoxylum americanum. see prickly ash, under
         prickly.
         1913 webster
see also:
xanthoxylum americanum prickly ash prickly