Used for a bounded area, range, or degree. Often appears in compounds or set phrases like 域を出ない (does not go beyond a certain level) or 域に達する (reaches a certain stage).
彼の実力はまだその域に達していない。
His ability hasn't reached that level yet.
この問題は専門家の域に属する。
This problem belongs to the domain of experts.
His opinion is still nothing more than speculation.
Her piano skill has reached the level of a master.
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.
area; region; district; locality
territory; domain · field; area; sphere; realm · domain; region
area; zone; district; section
sea area; waters
the whole area; the entire region; all parts (of) · the whole field (of study); every field; the whole gamut
wide area; broad region · wide view; zoomed-out view
sacred precincts; sanctuary; holy ground · off-limits issue; taboo topic; no-go area
band; zone; range · bandwidth
The kanji 域 originally means 'boundary' or 'region'. The reading いき is the on'yomi (Sino-Japanese reading).
drainage basin; river basin; watershed
waters; water area
range; register; compass
airspace
within the area; inside the region
regional revitalization; local revitalization
municipal area; city limits; city territory
Shinto shrine precincts · holy precincts; sanctuary
outside the area; outside the zone; out of bounds
scope of work; area of responsibility; range of duties · workplace; place of work
broadband; wideband
vocal range; range of voice; register
western regions of China
theater of war; war area; battlefield
range (of a function)
entering a zone; entry into an area
yen bloc; yen area
leaving an area; exiting a zone
market; business field; commercial sphere
sphere; domain; area
boundary; border; precinct; grounds
cemetery area; burial ground