alveolus
al-ve-o-lus
noun
A tiny air sac in the lungs where oxygen and carbon dioxide are exchanged.
"Oxygen diffuses from the alveolus into the bloodstream."
noun
A small pit or cavity, such as the socket for a tooth.
"The tooth fits securely within its dental alveolus."
Thesaurus
Synonyms: air cell, air sac, tooth socket