Source : Webster's Revised Unabridged Dictionary (1913)

Hydrazine \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.

Source : WordNet®

hydrazine
     n : a colorless fuming corrosive liquid; a powerful reducing
         agent; used chiefly in rocket fuels