1. Plural of alveolus; tiny air sacs in the lungs where gas exchange occurs between air and blood.
Usage: anatomy; medical
2. Small cavities or recesses in various tissues or structures, such as in bone or glandular tissue.
Usage: anatomy; general

Examples

• Oxygen enters the bloodstream through the alveoli in the lungs.
• The alveoli are lined with a thin membrane that allows gas exchange.
• Damage to the alveoli can result in reduced oxygen absorption.
• Each lung contains millions of tiny alveoli.
• Diseases like emphysema destroy the alveoli over time.
• The alveoli expand and contract with each breath.