\Pyr"i*dine\, n. [From Gr. ? fire.] (Physiol. Chem.)
A nitrogenous base, {C5H5N}, obtained from the distillation
of bone oil or coal tar, and by the decomposition of certain
alkaloids, as a colorless liquid with a peculiar pungent
odor. It is the nucleus of a large number of organic
substances, among which several vegetable alkaloids, as
nicotine and certain of the ptoma["i]nes, may be mentioned.
See {Lutidine}.