uracil urachus • uraemic · · · Info · Definitions · Synonyms · Characters · · uracil · · Text Latin · · Script 6 · · Length Definitions · · · (noun) a base containing nitrogen that is found in RNA (but not in DNA) and derived from pyrimidine; pairs with adenine. Synonyms: U. · · Noun Definition 1 Synonyms · · · u · · Synonym 1 Characters · · a latin small letter a U+0061 c latin small letter c U+0063 i latin small letter i U+0069 l latin small letter l U+006C r latin small letter r U+0072 u latin small letter u U+0075