- The vacuum valve opens to admit air.
- Backsiphonage protection shall include provision to admit air directly into the reduced pressure zone via a separate channel from the water discharge channel.
- A framed opening, as in a wall, door, or window, fitted with fixed or movable horizontal slats for admitting air and light and shedding rain.
- It was painful to admit that I was wrong.
- A lantern - shaped cupola on the roof of a medieval building for admitting air and providing for the escape of smoke.