Pyridine \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.

Source: Webster's Revised Unabridged Dictionary (1913)