The Collaborative International Dictionary of English v.0.48:

Creosote \Cre"o*sote\ (kr[=e]"[-o]*s[=o]t), n. [Gr. kre`as, gen.
   kre`ws, flesh + sw`zein to preserve.] (Chem.)
   Wood-tar oil; an oily antiseptic liquid, of a burning smoky
   taste, colorless when pure, but usually colored yellow or
   brown by impurity or exposure. It is a complex mixture of
   various phenols and their ethers, and is obtained by the
   distillation of wood tar, especially that of beechwood.
   [1913 Webster]

   Note: It is remarkable as an antiseptic and deodorizer in the
         preservation of wood, flesh, etc., and in the
         prevention of putrefaction; but it is a poor germicide,
         and in this respect has been overrated. Smoked meat, as
         ham, owes its preservation and taste to a small
         quantity of creosote absorbed from the smoke to which
         it is exposed. Carbolic acid is phenol[1] proper,
         while creosote is a mixture of several phenols.
         [1913 Webster]

   Coal-tar creosote (Chem.), a colorless or yellow, oily
      liquid, obtained in the distillation of coal tar, and
      resembling wood-tar oil, or creosote proper, in
      composition and properties.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Creosote \Cre"o*sote\, v. t. [imp. & p. p. Creosoted
   (-s?"t?d); p. pr. & vb. n. Creosoting.]
   To saturate or impregnate with creosote, as timber, for the
   prevention of decay.

WordNet (r) 3.0 (2006):

creosote
    n 1: a colorless or yellowish oily liquid obtained by
         distillation of wood tar; used as an antiseptic
    2: a dark oily liquid obtained by distillation of coal tar; used
       as a preservative for wood [syn: creosote, coal-tar
       creosote]
    v 1: treat with creosote; "creosoted wood"