- noun a device that causes fresh air to pass into a room or building
- A device or opening in a room or building through which fresh air enters the enclosure and stale air is expelled.
- A pivoted sash or framework, outfitted with hinged panes of glass that may be opened without opening the sash.
- noun a machine which pumps air into and out of the lungs of someone who has difficulty in breathing
- a machine that keeps air moving in and out of the lungs of a patient who cannot breathe unaided
- noun an opening which allows fresh air to come in, or a machine which pumps fresh air into a room and extracts stale air