noun.
A colorless crystalline compound, H3NO, explosive when heated, that is used as a reducing agent and in organic synthesis.
The Century Dictionary and Cyclopedia
noun.
A colorless basic compound, NH2OH, prepared by the reduction of various oxygen derivatives of nitrogen.
the GNU version of the Collaborative International Dictionary of English
noun.
A nitrogenous, organic base, NH2.OH, resembling ammonia, and produced by a modified reduction of nitric acid. It is usually obtained as a volatile, unstable solution in water. It acts as a strong reducing agent.