The Collaborative International Dictionary of English v.0.48:

Melanuric \Mel`a*nu"ric\, a. [Melam + urea.] (Chem.)
   Pertaining to, or designating, a complex nitrogenous acid
   obtained by decomposition of melam, or of urea, as a white
   crystalline powder; -- called also melanurenic acid.
   [1913 Webster]