Cyanate \Cy"a*nate\ (s?"?-n?t), n. [Cf. F. cuanate. See {Cyanic}.] (Chem.) A salt of cyanic acid. {Ammonium cyanate} (Chem.), a remarkable white crystalline substance, {NH4.O.CN}, which passes, on standing, to the organic compound, urea, {CO.(NH2)2}.