Al*ve"o*lus (#), n.; pl. Alveoli (#). [L., a small hollow or cavity, dim. of alveus: cf. F. alv'eole. See Alveary.]
1.
A cell in a honeycomb.
2. Zool.
A small cavity in a coral, shell, or fossil
3. Anat.
A small depression, sac, or vesicle, as the socket of a tooth, the air cells of the lungs, the ultimate saccules of glands, etc.
© Webster 1913.