mail slot mail service • mail train · · · Info · Definitions · Characters · · mail slot · · Text Common · · Latin · · Scripts 9 · · Length 2 · · Syllables Definitions · · · (noun) a slot (usually in a door) through which mail can be delivered. Synonyms: mail slot. · · Noun Definition 1 Characters · · space U+0020 a latin small letter a U+0061 i latin small letter i U+0069 l latin small letter l U+006C m latin small letter m U+006D o latin small letter o U+006F s latin small letter s U+0073 t latin small letter t U+0074