airspace

Etymology

air + space

noun

1. (politics, aviation) A specified portion of the atmosphere, especially that under the technical aviation control and/or jurisdiction of a particular state over which territory (and territorial waters) it lies.
   Various European countries transferred the aviation control of their adjoining airspace to Eurocontrol, while each retaining legal jurisdiction.
   Haines has previous experience of dealing with a hugely disruptive crisis. He said: "I left the railway in 2008 and went to the Civil Aviation Authority. And within a few months I was in the middle of an Icelandic volcanic storm. Eyafjallajokull closed airspace across northern Europe. March 25 2020, “Network News: Railway working with government to combat crisis”, in Rail, page 7
2. (aviation) that part of the sky designated for the sole use of aircraft.
3. (broadcasting) Space (i.e. a few neighboring frequencies) available for broadcasting within a particular frequency band.
   The legalisation of free radios caused a bitter fight for airspace.
4. The portion of an enclosed area which contains air, especially breathable air.
5. (construction) The cavity in a cavity wall containing air for insulation.