Tokyo is the center of the metropolitan area.
This region is developing as an economic bloc.
Technical mathematical term for a category in the sense of category theory. Rare outside specialized contexts.
In category theory, a category consists of objects and morphisms.
区域 denotes a physically demarcated district or area, whereas 圏 as a suffix often points to a conceptual or functional sphere of influence rather than a fixed boundary.
域 is another suffix meaning 'zone' or 'region' (e.g. 領域), but 圏 more strongly implies a sphere of influence, reach, or classification rather than a plain area.
権 means 'right' or 'authority' and is pronounced identically to 圏, but the two suffixes have entirely unrelated meanings.
The kanji 圏 originally meant 'enclosure' or 'circle' in Chinese. In Japanese, it is used as a suffix to denote a sphere, range, or zone, and in mathematics for 'category'.
emphasis mark; dot used for emphasis
category theory
cirque; corrie; cwm
great circle
lithosphere
hour circle; circle of declination