• 圏内けんない — within the area / inside the sphere
• 圏外けんがい — outside the area / out of range
• 成層圏せいそうけん — stratosphere
• 首都圏しゅとけん — metropolitan area
• 大気圏たいきけん — atmosphere
• 暴風圏ぼうふうけん — storm zone
• 文化圏ぶんかけん — cultural sphere

The radical 囗 (くにがまえ) literally represents an enclosure or surrounding wall. Combined with the sound element 巻ケン, it conveys the sense of a bounded circle or sphere. This is why 圏 is used in words about zones, spheres, and defined ranges.