pneumothorax Syllabification: (pneu·mo·tho·rax)Pronunciation: /ˌn(y)o͞omōˈTHôˌraks/Definition of pneumothorax noun Medicine the presence of air or gas in the cavity between the lungs and the chest wall, causing collapse of the lung. pneumothorax in other Oxford dictionaries Definition of pneumothorax in the British & World English dictionary
