The Collaborative International Dictionary of English v.0.48:

Isocyanuric \I`so*cy`a*nu"ric\, a. [Iso- + cyanuric.] (Chem.)
   Designating, or pertaining to, an acid isomeric with cyanuric
   acid, and called also fulminuric acid. See under
   Fulminuric.
   [1913 Webster]