in Geography, an appellation given to the dominions of a duke.

Duchy Court, a court where all matters belonging to the duchy or county palatine of Lancaster are decided by decree of the chancellor of that court.

The origin of this court was in Henry IV's time, who obtained the crown by the deposition of Richard II, and having the duchy of Lancaster by descent, in right of his mother, became seized thereof as king, not as duke: So that all the liberties, franchises, and jurisdictions of the said county passed from the king by his great seal, and not by livery or attornment, as the earldom of March, and other possessions, which descended to him by other ancestors than the king's did. Henry IV, by authority of parliament severed the possessions, liberties, &c. of the said duchy from the crown; but Edward IV restored them to their former nature.

The officers belonging to this court are, a chancellor, attorney general, receiver-general, clerk of the court, and messenger; besides the assistants, as an attorney in the exchequer, another in chancery, and four counsellers.