first-class mail first-class • first-conceived · · · Info · Definitions · Synonyms · Characters · · first-class mail · · Text Common · · Latin · · Scripts 16 · · Length Definitions · · · (noun) mail that includes letters and postcards and packages sealed against inspection. Synonyms: first class, 1st class, 1st-class mail. · · Noun Definition 1 Synonyms · · · first class · · Synonym 1 1st class · · Synonym 2 1st-class mail · · Synonym 3 excellent · · Synonym 4 first-class · · Synonym 5 fantabulous · · Synonym 6 splendid · · Synonym 7 Characters · · space U+0020 - hyphen-minus U+002D a latin small letter a U+0061 c latin small letter c U+0063 f latin small letter f U+0066 i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D r latin small letter r U+0072 s latin small letter s U+0073 t latin small letter t U+0074