WordWeight : Weighing the Words

Pronunciation : Me`di*as"tine, Me`di*as*ti"num
Part of Speech : n.
Etymology : [NL. mediastinum, fr. L. medius middle; cf. mediastinus helper, a menial servant, LL. mediastinus equiv. to medius: cf F. m?diastin.] (Anat.)
Definition : Defn: A partition; a septum; specifically, the folds of the pleura (and the space included between them) which divide the thorax into a right and left cavity. The space included between these folds of the pleura, called the mediastinal space, contains the heart and gives passage to the esophagus and great blood vessels.
Source : Webster's Unabridged Dictionary, 1913