The Collaborative International Dictionary of English v.0.48:

Styrax \Sty"rax\, n. [L. styrax, storax, Gr. ?. See Storax.]
   1. (Bot.) A genus of shrubs and trees, mostly American or
      Asiatic, abounding in resinous and aromatic substances.
      Styrax officinalis yields storax, and Styrax Benzoin
      yields benzoin.
      [1913 Webster]

   2. Same as Storax.
      [1913 Webster]

WordNet (r) 3.0 (2006):

styrax
    n 1: any shrub or small tree of the genus Styrax having fragrant
         bell-shaped flowers that hang below the dark green foliage