xanthinePronunciation: /ˈzanθiːn/Definition of xanthine noun [mass noun] Biochemistry a crystalline compound found in blood and urine which is an intermediate in the metabolic breakdown of nucleic acids to uric acid. A purine derivative; chemical formula: C5H4N4O2 [count noun] any of the derivatives of this, including caffeine and related alkaloids. Origin: mid 19th century: from xanthic + -ine4xanthine in other Oxford dictionaries Definition of xanthine in the US English dictionary
