The term CRESOTE SOURCE is related to the three letter word TAR. TAR is a black, viscous liquid that is produced by the destructive distillation of organic materials such as wood, coal, or peat. It is often used as a preservative for wood, and is also used in road construction and roofing. Cresote source is a type of TAR that is derived from the distillation of coal TAR and is used in the production of creosote, which is used as a wood preservative.