ventilation

Short definition from Wiktionary

Noun

1. 1
   The replacement of stale or noxious air with fresh.
2. 2
   The mechanical system used to circulate and replace air.
3. 3
   An exchange of views during a discussion.
4. 4
   The public exposure of an issue or topic.
5. 5
   The bodily process of breathing; the inhalation of air to provide oxygen, and the exhalation of spent air to remove carbon dioxide.
6. 6
   The mechanical system used to assist breathing.