Tiny air sacs in the lungs where gas exchange occurs between inhaled air and blood. These microscopic structures are surrounded by capillaries and allow oxygen to enter the bloodstream while carbon dioxide is removed.
From Latin 'alveolus' meaning small cavity or hollow, diminutive of 'alveus' (trough or basin). The term was adopted in anatomy to describe any small socket-like structure, but became most associated with lung air sacs.
Try Another Word