\Hy"dra*zine\, n. [Hydr- + azo- + -ine.] (Chem.)
Any one of a series of nitrogenous bases, resembling the
amines and produced by the reduction of certain nitroso and
diazo compounds; as, methyl hydrazine, phenyl hydrazine, etc.
They are derivatives of hydrazine proper, {H2N.NH2}, which is
a doubled amido group, recently (1887) isolated as a stable,
colorless gas, with a peculiar, irritating odor. As a base it
forms distinct salts. Called also {diamide}, {amidogen}, (or
more properly {diamidogen}), etc.