A structure, often a reinforced underground shelter designed to give protection against air raids.

Any recreational activity performed in flight or during freefall from a flight through the atmosphere.

(meteorology) A particular volume of air, especially one having a roughly uniform temperature, pressure and water vapour content.

A military officer who serves as an adjutant to a higher-ranking officer, prince or other high political dignitary.

To mechanically cool a space or an entire structure.

Alternative form of airbridge.

(idiomatic) To expose to air; to leave open or spread out, as to allow odor or moisture to dissipate. / (by extension) To discuss in the open; to address an issue or conflict that has long been avoided.

A feature included on some cellular phones or laptops which disables the radio, thus precluding any interference with avionics. In this mode the phone's stand-alone features (such as its games or scheduler) can be used safely in environments requiring minimal radio interference.

(obsolete, inorganic chemistry) carbon dioxide, carbonic acid

(obsolete, chemistry) silicon tetrafluoride