Alveolus
Pronunciation : Al*ve"o*lus
Part of Speech : n.; pl. Alveoli.
Etymology : [L., a small hollow or cavity, dim. of alveus: cf. F. alv?ole. See Alveary.]
Definition : 1. A cell in a honeycomb.
2. (Zo?l.)
Defn: A small cavity in a coral, shell, or fossil
3. (Anat.)
Defn: A small depression, sac, or vesicle, as the socket of a tooth, the air cells of the lungs, the ultimate saccules of glands, etc.
Source : Webster's Unabridged Dictionary, 1913