Alveolus

||Al*ve"o*lus (ăl*vē"?*lŭs), n.; pl. Alveoli (-lī). [L., a small hollow or cavity, dim. of alveus: cf. F. alvéole. See Alveary.] 1. A cell in a honeycomb.

2. (Zoöl.) 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.