from the GNU version of the Collaborative International Dictionary of English
- n. a valve to regulate the admission or egress of air; esp. a valve which opens inwardly in a steam boiler and allows air to enter.
- n. etc. See under Air. Ball, Check, etc.
Sorry, no etymologies found.
The air cells may all be represented as soft-walled bags opening freely into the bellows ” there being, so far as anatomists yet know, no valves or corresponding contrivances anywhere except at the glottis, which corresponds with the nozzle and air valve both, of our bellows.