air sac

Từ điển WordNet v3.1 - WordNet Dictionary

noun

1. a tiny sac for holding air in the lungs;
formed by the terminal dilation of tiny air passageways
• Syn:
alveolus, air cell
• Derivationally related forms:
alveolate (for: alveolus)
• Hypernyms:
sac
• Part Holonyms:
lung
2. any of the thin-walled extensions of the tracheae of insects
• Hypernyms:
sac
• Part Holonyms:
insect
3. any of the membranous air-filled extensions of the lungs of birds
• Hypernyms:
sac
• Part Holonyms:
bird