red-letter day red-letter • red-lettered · · · Info · Definitions · Characters · · red-letter day · · Text Common · · Latin · · Scripts 14 · · Length 4 · · Syllables Definitions · · · (noun) a memorably happy or noteworthy day (from the custom of marking holy days in red on church calendars). Synonyms: red-letter day. · · Noun Definition 1 Characters · · space U+0020 - hyphen-minus U+002D a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 l latin small letter l U+006C r latin small letter r U+0072 t latin small letter t U+0074 y latin small letter y U+0079