The Collaborative International Dictionary of English v.0.48:
Xanthoxylum \Xan*thox"y*lum\, 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.
Note: The commonest species in the Northern United States is
Xanthoxylum Americanum. See Prickly ash, under