COAL TAR n.
A thick, black, tarry liquid, obtained by the distillation of bituminous coal in the manufacture of illuminating gas; used for making printer's ink, black varnish, etc. It is a complex mixture from which many substances have been obtained, especially hydrocarbons of the benzene or aromatic series.
COEFFICIENT n.
A number, commonly used in computation as a factor, expressing the amount of some change or effect under certain fixed conditions as to temperature, length, volume, etc.; as, the coefficient of expansion; the coefficient of friction. Arbitrary coefficient (Math.), a literal coefficient placed arbitrarily in an algebrai…