Word Study
mediastinum
WORDNET DICTIONARY
Noun mediastinum has 1 sense
CIDE DICTIONARY
mediastinum, n. [NL. mediastinum, fr. L. medius middle; cf. mediastinus helper, a menial servant, LL. mediastinus equiv. to medius: cf F. médiastin.].
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. [1913 Webster]
OXFORD DICTIONARY
mediastinum, n. (pl. mediastina) Anat. a membranous middle septum, esp. between the lungs.
Derivative
mediastinal adj.
Etymology
mod.L f. med.L mediastinus medial, after L mediastinus drudge f. medius middle
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