首都圏【しゅとけん】
Greater Tokyo Metropolitan area, metropolitan area (of a capital)
圏外【けんがい】
(being) out of range (e.g. mobile network, radar, missiles), (being) out of contention, (being) beyond influence
圏内【けんない】
(being) within range (radio, commuting, etc.), (being) within the sphere (e.g. of influence)
北極圏【ほっきょくけん】
Arctic Circle, the Arctic
成層圏【せいそうけん】
stratosphere
勢力圏【せいりょくけん】
sphere of influence