n. — Outdoors
a light jacket serving as protection from the wind.
A wind shell is a wind-proof jacket intended mostly for sports such as running, hiking, cycling and general outdoor use. Chart 1 shows that the term is most prevalent in South Africa, then Canada, but is used very widely in the English-speaking world.
See COD-2, s.v. "shell" (6), which is marked "N Amer.", and Gage-5, s.v. "wind-shell", which is marked "Cdn", which we cannot confirm with our data.
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Chart 1: Internet Domain Search, 13 Apr. 2015