grand duke definition by Webster's New World
Webster's New World College Dictionary Copyright © 2010 by Wiley Publishing, Inc., Cleveland, Ohio. Used by arrangement with John Wiley & Sons, Inc.
- the sovereign ruler of a grand duchy, ranking just below a king
- in czarist Russia, a prince of the royal family
grand duke definition by American Heritage Dictionary
- A nobleman who is the sovereign of a grand duchy.
- A son or grandson of a czar in the male line.
- Used as the title for such a nobleman.