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Medical Term:


Pronunciation: ā′trē-ŭm, ā′trē-ă


  1. A chamber or cavity to which are connected several chambers or passageways.
  2. That part of the tympanic cavity that lies immediately deep to the tympanic membrane.
  3. In the lung, a subdivision of the alveolar duct from which alveolar sacs open.

Synonym(s): atrium of heart

[L. entrance hall]