Emphysema \Em`phy*se"ma\, n. [NL., from Gr. ? inflation, fr. ? to inflate; ? in + ? to blow: cf. F. emphys[`e]me.]

(Med.) A swelling produced by gas or air diffused in the cellular tissue.

Emphysema of the lungs, Pulmonary emphysema (Med.), a common disease of the lungs in which the air cells are distended and their partition walls ruptured by an abnormal pressure of the air contained in them.

Source: Webster's Revised Unabridged Dictionary (1913)