• Duchy
  Duchy
  A duchy is a territory, fief, or domain ruled by a duke or duchess.Some duchies were sovereign in areas that would become unified realms only during the Modern era . In contrast, others were subordinate districts of those kingdoms that unified either partially or completely during the Medieval era...
  
  , the territory ruled by a duke
• the office of a duke
  Duke
  A duke or duchess is a member of the nobility, historically of highest rank below the monarch, and historically controlling a duchy...
  
  

Places

• Dukedom, Kentucky and Tennessee
  Dukedom, Kentucky and Tennessee
  Dukedom is an unincorporated community in both Graves County, Kentucky and Weakley County, Tennessee in the United States, straddling the state line in the western part of both states...
  
  , an unincorporated community in Graves County, Kentucky and Weakley County, Tennessee

Computer games

• Dukedom (game), a land management game (an expanded version of Hamurabi
  Hamurabi
  Hamurabi is a text-based game of land and resource management and is one of the earliest computer games. Its name is a shortening of Hammurabi, reduced to fit an eight-character limit.-History:...
  
  )