Quin"o*line (?), n. [Quinine + L. oleum oil + -ine.] (Chem.) A nitrogenous base, C₉H₇N obtained as a pungent colorless liquid by the distillation of alkaloids, bones, coal tar, etc. It the nucleus of many organic bodies, especially of certain alkaloids and related substances; hence, by extension, any one of the series of alkaloidal bases of which quinoline proper is the type. [Written also chinoline.]

• (chemistry) Any of a class of aromatic heterocyclic compounds containing a benzene ring fused with a ring of five carbon atoms and an nitrogen atom; especially the simplest one, C9H7N.