thoracic duct thoracic cavity • thoracic medicine · · · Info · Definitions · Characters · · thoracic duct · · Text Common · · Latin · · Scripts 13 · · Length 4 · · Syllables Definitions · · · (noun) the major duct of the lymphatic system. Synonyms: thoracic duct. · · Noun Definition 1 Characters · · space U+0020 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 o latin small letter o U+006F r latin small letter r U+0072 t latin small letter t U+0074 u latin small letter u U+0075