n.
Pronunciation: ˌ nü-m ə - ' tho ̇ r- ˌ aks, ˌ nyü-
Function: noun
Etymology: New Latin
Date: 1821
: a condition in which air or other gas is present in the pleural cavity and which occurs spontaneously as a result of disease or injury of lung tissue, rupture of air-filled pulmonary cysts, or puncture of the chest wall or is induced as a therapeutic measure to collapse the lung