noun.
Any of various chemical compounds containing two amino groups, especially hydrazine.
The Century Dictionary and Cyclopedia
noun.
The name of a class of chemical compounds formed by substituting one or more alcohol radicals for hydrogen in a double molecule made up of two ammonia molecules.
the GNU version of the Collaborative International Dictionary of English
noun.
A compound containing two amido groups united with one or more basic or positive radicals, -- as contrasted with a diamide.