'alveolus' definitions:

Definition of 'alveolus'

(from WordNet)
noun
A tiny sac for holding air in the lungs; formed by the terminal dilation of tiny air passageways [syn: alveolus, air sac, air cell]
noun
A bony socket in the alveolar ridge that holds a tooth [syn: tooth socket, alveolus]

Synonyms of 'alveolus'

From: Moby Thesaurus