The Collaborative International Dictionary of English v.0.48:

Vanillin \Va*nil"lin\, n. (Chem.)
   A white crystalline aldehyde having a burning taste and
   characteristic odor of vanilla. It is extracted from vanilla
   pods, and is also obtained by the decomposition of coniferin,
   and by the oxidation of eugenol.
   [1913 Webster]

WordNet (r) 3.0 (2006):

vanillin
    n 1: a crystalline compound found in vanilla beans and some
         balsam resins; used in perfumes and flavorings