• airshed •
Pronunciation: er-shed • Hear it!
Part of Speech: Noun
Meaning: 1. (UK) Aircraft hangar. 2. The coherent air supply of a region with regard to the spread of pollutants. 3. The region supplied by a consistent source of air.
Notes: Since I find the first meaning only in British dictionaries and I've never heard the word used in that sense, I presume it is favored in the UK. Like the vast majority of compounds, it is a lexical orphan.
In Play: Airsheds are hard to define because their edges are ragged: "The Chesapeake Bay airshed runs from New York state to North Carolina and west to Indiana, Kentucky, and Tennessee." They are usually determined by geological factors: "Prince George's airshed is strongly affected by its location at the confluence of two large rivers: the Nechako River and the Fraser River."
Word History: Today's compound noun was created by loan translation in the 1920s from German Luftscheide "airshed", created by analogy with Wasserscheide "watershed". English picked up air from French, which inherited it from Latin aer. Air replaced native lyft, cousin of German Luft "air". Latin came by its word from the same source Greek inherited aenai "to blow, breath", PIE awer- "to blow", same source as German wehen "to blow", Russian veyat' "to blow lightly" and veter "wind", and Lithuanian vėjas "wind". Shed came from the same source as shade, since it originally referred to the barest form of shelter. Shade has Germanic cousins in German Schatten "shade" and Dutch schaduw "shade". All go back to PIE skoto- "shade, dark", source also of Greek skotos "darkness", Irish scáth "shade, shadow", and Breton skeud "shade". (Barbara Beeton, a very active Agoran, thought airshed is so relevant to environmental discussions as to make a topical Good Word. We agree.)
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