圏

storm zone

urban area; metropolitan area; metropolitan region

communist bloc; Iron Curtain

Military

air defense identification zone; ADIZ

eurozone; euro zone; euro area

atmosphere

Greater East Asia Co-Prosperity Sphere

troposphere

business region; marketing area; commercial sphere; trading area; region in which a business operates

Astronomy

gravitational field (of a celestial body); sphere of gravitation; gravisphere

Islamic world; Muslim world

sphere of influence

Antarctic Circle; the Antarctic

Baseball

scoring position

German-speaking countries; German language sphere

thermosphere

French-speaking world; francophone world; francophonie

co-prosperity sphere

Biology

home range

countries where Chinese characters are used or were historically used

Aviation

control zone

mesosphere

outer atmosphere

great circle