realm

A realm is an area that is ruled by something. If you are a controlling cook who doesn’t like anyone to do anything else in the kitchen, then the kitchen is your realm.

Realm comes from the French for kingdom, but since there aren’t so many kings or queens left in the world, you’ll more often find it referring to non-royal spheres. That could be the sphere of a special kind of knowledge, like the realm of biology, or the political realm. Or it could be an area dominated by some group. Little Italy was famously the realm of the mafia; Hollywood is the realm of film stars.

Definitions of realm
1

n a domain in which something is dominant

“the rise of the realm of cotton in the south”
Synonyms:
kingdom, land
Types:
lotus land, lotusland
an idyllic realm of contentment and self-indulgence
Type of:
area, arena, domain, field, orbit, sphere
a particular environment or walk of life

n the domain ruled by a king or queen

Synonyms:
kingdom
Examples:
Numidia
an ancient kingdom (later a Roman province) in North Africa in an area corresponding roughly to present-day Algeria
Type of:
demesne, domain, land
territory over which rule or control is exercised

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

“it was a limited realm of discourse”
“the realm of the occult”
Synonyms:
region
Type of:
domain, knowledge base, knowledge domain
the content of a particular field of knowledge

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