fiefdom

noun2

1. •
   Any organization in the control of a dominant individual.

   • “[Bill Clinton] was just walking around, looking in all the offices, like he was surveying his fiefdom. He had a big grin on his face.” — 2008
2. •
   (historical) The estate controlled by a feudal lord.

   • The duke's fiefdom had been greatly expanded as a reward for his dutiful military service on behalf of the king.