diamide

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.
   [1913 Webster]
    

Diamide \Di*am"ide\ (?; 104), n. [Pref. di- + amide.] (Chem.)
   Any compound containing two amido groups united with one or
   more acid or negative radicals, -- as distinguished from a
   diamine. Cf. Amido acid, under {Amido}, and Acid amide, under
   {Amide}.
   [1913 Webster]