creosote

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A colorless to yellowish oily liquid containing phenols and creosols, obtained by the destructive distillation of wood tar, especially from the wood of a beech, and formerly used as an expectorant in treating chronic bronchitis.
• noun A yellowish to greenish-brown oily liquid containing phenols and creosols, obtained from coal tar and used as a wood preservative and disinfectant. It can cause severe neurological disturbances if inhaled in strong concentrations.
• transitive verb To treat or paint with creosote.

from The Century Dictionary.

• To apply creosote or a solution of creosote to; treat with creosote: as, to creosote wood to prevent its decay.
• noun A substance first prepared from wood-tar, from which it is separated by repeated solution in potash, treatment with acids, and distillation.

from the GNU version of the Collaborative International Dictionary of English.

• noun (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.
• noun (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.
• transitive verb To saturate or impregnate with creosote, as timber, for the prevention of decay.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun A pale yellow oily liquid, containing phenols and similar compounds, obtained by the destructive distillation of wood tar, once used medicinally.
• noun A similar brown liquid obtained from coal tar used as a wood preservative.
• noun uncountable The creosote bush.
• verb To apply creosote.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• verb treat with creosote
• noun a dark oily liquid obtained by distillation of coal tar; used as a preservative for wood
• noun a colorless or yellowish oily liquid obtained by distillation of wood tar; used as an antiseptic