1. lung condition causing breathing impairment: a chronic medical disorder of the lungs in which the air sacs are dilated or enlarged and lack flexibility, so that breathing is impaired and infection sometimes occurs
2. enlargement caused by retained gas: an unusual enlargement of an organ or body tissue caused by retention of air or other gas
[Mid-17th century. Via late Latin< Greek emphusēma "swelling" < emphusan "inflate" < phusan "blow"]
