realm

nouns

a domain in which something is dominant

"the untroubled kingdom of reason"; "a land of make-believe"; "the rise of the realm of cotton in the south"

kingdom, land, realm

the domain ruled by a king or queen

kingdom, realm

a knowledge domain that you are interested in or are communicating about

"it was a limited realm of discourse"; "here we enter the region of opinion"; "the realm of the occult"

realm, region