coal-tar

Noun

coal tar (countable and uncountable, plural coal tars)

1. 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...1847, editorial staff, “New Lubricating Compound”, in Scientific American, series 1, Volume 3, Issue 9, page 68