Home › Words › U › urocyaninurocyaninurocyanin · noun — A blue pigment sometimes observed in the urine in certain diseases, especially scarlet fever.Definition from Wiktionary (CC BY-SA 3.0).EtymologyFrom uro- + cyanin?nounA blue pigment sometimes observed in the urine in certain diseases, especially scarlet fever.Definitions & examples from Wiktionary (CC BY-SA 3.0).