The Collaborative International Dictionary
Ureide
Ureide \U"re*ide\, n. (Chem.) Any one of the many complex derivatives of urea; thus, hydantoin, and, in an extended dense, guanidine, caffeine, et., are ureides. [Written also ureid.]
Wiktionary
ureide
n. (context chemistry English) any compound, of general formula R-CO-NH-CO-NH2 or R-CO-NH-CO-NH-CO-R', formally derived by the acylation of urea