third-class mail third class • third council of constantinople · · · Info · Definitions · Synonyms · Characters · · third-class mail · · Text Common · · Latin · · Scripts 16 · · Length 3 · · Syllables Definitions · · · (noun) mail consisting of printed matter qualifying for reduced postal rates. Synonyms: third-class mail, third class. · · Noun Definition 1 Synonyms · · · third class · · Synonym 1 Characters · · space U+0020 - hyphen-minus U+002D a latin small letter a U+0061 c latin small letter c U+0063 d latin small letter d U+0064 h latin small letter h U+0068 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