Pronunciation: (hī'dru-zēn"),[key] —n. 1. Also called diamine. a colorless, oily, fuming liquid, N2H4, that is a weak base in solution and forms a large number of salts resembling ammonium salts: used chiefly as a reducing agent and a jet-propulsion fuel.
2. a class of substances derived by replacing one or more hydrogen atoms in hydrazine by an organic group.