uracilPronunciation: /ˈjʊərəsɪl/Definition of uracil noun [mass noun] Biochemistry a compound found in living tissue as a constituent base of RNA. In DNA it is replaced by thymine. A pyrimidine derivative; chemical formula: C4H4N2O2 Origin: late 19th century: from ur(ea) + ac(etic) + -iluracil in other Oxford dictionaries Definition of uracil in the US English dictionary
