The Collaborative International Dictionary of English v.0.48:

Storax \Sto"rax\, n. [L. storax, styrax, Gr. ?. Cf. Styrax.]
   Any one of a number of similar complex resins obtained from
   the bark of several trees and shrubs of the Styrax family.
   The most common of these is liquid storax, a brown or gray
   semifluid substance of an agreeable aromatic odor and
   balsamic taste, sometimes used in perfumery, and in medicine
   as an expectorant.
   [1913 Webster]

   Note: A yellow aromatic honeylike substance, resembling, and
         often confounded with, storax, is obtained from the
         American sweet gum tree (Liquidambar styraciflua),
         and is much used as a chewing gum, called sweet gum,
         and liquid storax. Cf. Liquidambar.
         [1913 Webster]

WordNet (r) 3.0 (2006):

storax
    n 1: a vanilla-scented resin from various trees of the genus
         Styrax