air mass

• airmass

Perhaps a calque of German Luftmasse.

• (UK) IPA^(key): /ˈɛː mas/
• (US) IPA^(key): /ɛəɹ mæs/, /ɛːɹ mæs/

air mass (plural air masses)

1. (meteorology) A particular volume of air, especially one having a roughly uniform temperature, pressure and water vapour content. [from 19th c.]
   • 1939, ‘Cloudburst’, Time, 2 Jan 1939:

     After a 227-day drought ending with December temperatures above 90, a polar air mass collided with a wave of damp tropical air, condensed it in seven days of cloudburst.

   • 2013 December 31, Bridie Jabour, The Guardian:

     The mercury has been soaring in the state since the weekend because of an air mass hovering over Queensland.

• Marissa, Massari