函牍 hándú correspondence Origin Definitions Defs Strokes Stroke Words Sentences Sents hándú correspondence 函 hán noun letter (literary or formal) a letter; correspondence; official document牍 牘 dú document (bound form) official document; letter; bookhándú books 函 hán case (bound form) a small box, case, or envelope; a protective cover for books or objects牍 牘 dú writing tablet (bound form) wooden tablet or slip used for writing in ancient times