Duchy
/ˈdʌtʃi/
Definition 1 of 2
Pro Tip 1/3Monarchy Ties
A duchy often has historical significance and links to the royal family. 
The duchy of Cornwall provides income for the Prince of Wales.
Pro Tip 2/3Not a Country
Do not confuse a duchy with a country; it's a subdivision, usually within a country. 
Though the duchy of Luxembourg existed, it eventually became a separate country.
Pro Tip 3/3Cultural References
Duchies are prominent in historical and fantasy literature, often symbolizing wealth or power. 
In the novel, the hero travels to a duchy to seek an audience with the duke.