dukedom

In Galileo’s time, the papacy was a political power of significance, gobbling up failed dukedoms elsewhere, merging them into what became known as the “papal states.”
Galileo the Science Publicist - Issue 103: Healthy Communication|Mario Livio|July 14, 2021|Nautilus
After her husband, Andrew, inherited the dukedom in 1950, Debo found herself in charge of seven houses in short order.
The Duchess Tells All|Chloë Schama|November 25, 2010|DAILY BEAST
Francis Egerton succeeded to the dukedom at the age of twelve on the death of his brother, the 2nd duke.
Encyclopaedia Britannica, 11th Edition, Volume 4, Part 3|Various
You cannot give up your Dukedom, you cannot leave Stuttgart, and we cannot live apart.'
A German Pompadour|Marie Hay

Sitting at the large middle table she transacted the business of the Dukedom.
A German Pompadour|Marie Hay
Her hopes are ended, the doctors have been mistaken, there will be no heir to the Dukedom.
A German Pompadour|Marie Hay
Marlborough was received with transports in England, and raised to the dukedom of Marlborough.
Blackwood's Edinburgh Magazine, Volume 71, No. 436, February 1852|Various

British Dictionary definitions for dukedom

dukedom

/ (ˈdjuːkdəm) /

noun

another name for a duchy

the title, rank, or position of a duke

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012