域いき Noun English jmdict 1 noun (common) (futsuumeishi) region;limits;stage;level まず、私の活動範囲は、おもに養老川下流域です。 First off, my area of work is mainly in the lower reaches of the Yourou River.
整域せいいき Noun English jmdict 1 noun (common) (futsuumeishi) mathematics integral domain;ring with no divisors of zero