coal tar

noun coal tars

1. countable, uncountable A black, viscous tar made by the destructive distillation of coal (to make coke and town gas); it contains a great number of compounds including hydrocarbons and phenols; used in the preparation of medicinal soap and shampoo, and industrially for the manufacture of many products. Lewis Kirk, the inventor of the steam hammer, and John Dodsworth, of Reading, Penn. have invented a new compound which they say "experience has proved to be a superior compound for preventing friction. The invention is the union, under a high degree of heat, of oil with asphaltum, or with coal tar,