Where the air is unconfined:
— The concert was held in the open air.

synonyms: open, out-of-doors, outdoors.

Roget 338: air etc. (gas) 334; common air, atmospheric air; atmosphere; aerosphere^†.    open air; sky, welkin; blue sky; cloud etc. 353.    weather, climate, rise and fall of the barometer, isobar.    [Science of air] aerology, aerometry^†, aeroscopy^†, aeroscopy^†, aerography^†; meteorology, climatology; pneumatics; eudioscope^†, baroscope^†, aeroscope^†, eudiometer^†, barometer, aerometer^†; aneroid, baroscope^†; weather gauge, weather glass, weather cock.    exposure to the air, exposure to the weather; ventilation; aerostation^†, aeronautics, aeronaut.    ... show more

Dutch: laar
Polish: dwór