a. [ Pref. tri- + gen- + -ic. So named in reference to its composition, it being supposed to contain the radicals of three molecules of cyanic acid. ] (Chem.) Of, pertaining to, or designating, an acid, C4H7N3O2, obtained, by the action of the vapor of cyanic acid on cold aldehyde, as a white crystalline substance having a slightly acid taste and faint smell; -- called also ethidene-biuret or ethylidene-biuret. [ 1913 Webster ]