mediastinum mediastinotomy • mediate · · · Info · Definitions · Characters · · mediastinum · · Text Latin · · Script 11 · · Length Definitions · · · (noun) the part of the thoracic cavity between the lungs that contains the heart and aorta and esophagus and trachea and thymus. · · Noun Definition 1 Characters · · a latin small letter a U+0061 d latin small letter d U+0064 e latin small letter e U+0065 i latin small letter i U+0069 m latin small letter m U+006D n latin small letter n U+006E s latin small letter s U+0073 t latin small letter t U+0074 u latin small letter u U+0075