Fiefdom (noun)

1. A territory or sphere of influence over which someone has control or power.
2. A self-governing territory or domain.

Origin:

Late middle english: from old french feve, from medieval latin feodum, from latin feudum "fief", from germanic; related to fee.

Examples:

1. He ruled over his small fiefdom with an iron fist.
2. The company's CEO had complete control over his fiefdom.
3. The manager's department was a fiefdom, where he made all the decisions without consulting anyone.
4. The country was divided into many small fiefdoms, each ruled by a different warlord.
5. The region was a fiefdom of the powerful noble family.