(being) within range (radio, commuting, etc.); (being) within the sphere (e.g. of influence)
(being) out of range (e.g. mobile network, radar, missiles); (being) out of contention; (being) beyond influence
safety zone; buffer (e.g. against defeat)
one's daily milieu; neighbourhood; neighborhood; zone of life; sphere of life
the capital city (often Tokyo) area (typically within 50 km of city's centre) (center)
economic bloc; ecosystem (of services, goods, etc. within a company or consortium)
English-speaking world; English-speaking countries; Anglosphere
gravitational sphere (of a celestial body); gravitational field
Arctic Circle; the Arctic
urban area; metropolitan area; metropolitan region
greater metropolitan area; megalopolis; conurbation
communist bloc; Iron Curtain
emphasis mark (used in Japanese text in a way similar to underlining)
air defense identification zone; ADIZ
gravitational field (of a celestial body); sphere of gravitation; gravisphere
business region; marketing area; commercial sphere; trading area; region in which a business operates
Islamic world; Muslim world
Antarctic Circle; the Antarctic
German-speaking countries; German language sphere
French-speaking world; francophone world; francophonie
countries where Chinese characters are used or were historically used
sphere (e.g. of knowledge, influence)
eurozone; euro zone; euro area
public sphere; public domain
Greater China (incl. Hong Kong, Macao, Taiwan and sometimes Singapore)
sinophone world; Chinese-speaking world
Spanish-speaking world; Spanish-speaking countries
kanji cultural sphere; countries where Chinese characters are used or were historically used
hour circle; circle of declination
traffic area; traffic block
harm zone; people who will suffer the negative effects of new public facilities, infrastructure, etc. (e.g. pollution)
beneficiary zone; people who will enjoy the benefits of new public facilities, infrastructure, etc.
Grothendieck's Galois theory