The Collaborative International Dictionary of English v.0.48:

Styrolene \Sty"ro*lene\, n. (Chem.)
   An unsaturated hydrocarbon, C8H8, obtained by the
   distillation of storax, by the decomposition of cinnamic
   acid, and by the condensation of acetylene, as a fragrant,
   aromatic, mobile liquid; -- called also phenyl ethylene,
   vinyl benzene, styrol, styrene, and cinnamene.
   [1913 Webster]

WordNet (r) 3.0 (2006):

styrene
    n 1: a colorless oily liquid; the monomer for polystyrene [syn:
         styrene, cinnamene, phenylethylene, vinylbenzene]