n. 1. 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.
2. A yellowish to greenish-brown oily liquid containing phenols and creosols, obtained from coal tar and used as a wood preservative and formerly as a disinfectant. It can cause severe neurological disturbances if inhaled in strong concentrations.
3. A blackish residue formed, as on the inside of a flue, through condensation of volatile compounds released by incomplete combustion of wood or other fuel.