The Collaborative International Dictionary of English v.0.48:

Cresol \Cre"sol\ (kr[=e]"s[=o]l), n. [From Creosote.] (Chem.)
   Any one of three metameric substances, CH3.C6H4.OH,
   homologous with and resembling phenol. They are obtained from
   coal tar and wood tar, and are colorless, oily liquids or
   solids.

   Note: [Called also cresylic acid.]
         [1913 Webster]

WordNet (r) 3.0 (2006):

cresol
    n 1: any of three poisonous colorless isomeric phenols; derived
         from coal or wood tar; used as a disinfectant [syn:
         cresol, methyl phenol]