air_sac
1. [ noun ] (anatomy,zoology) any of the thin-walled extensions of the tracheae of insects
Related terms: sac insect
2. [ noun ] (anatomy,zoology) a tiny sac for holding air in the lungs; formed by the terminal dilation of tiny air passageways
Synonyms: alveolus air_cell
Related terms: sac lung
3. [ noun ] (anatomy,zoology) any of the membranous air-filled extensions of the lungs of birds
Related terms: sac bird
Similar spelling:   air_sock
  air_sick
  air_jacket
  air_gas