'Duke's coronet' definitions:

Definition of 'Duke's coronet'

From: GCIDE

Duke \Duke\ (d[=u]k), n. [F. duc, fr. L. dux, ducis, leader, commander, fr. ducere to lead; akin to AS. te['o]n to draw; cf. AS. heretoga (here army) an army leader, general, G. herzog duke. See Tue, and cf. Doge, Duchess, Ducat, Duct, Adduce, Deduct.]
1. A leader; a chief; a prince. [Obs.] [1913 Webster]
Hannibal, duke of Carthage. --Sir T. Elyot. [1913 Webster]
All were dukes once, who were "duces" -- captains or leaders of their people. --Trench. [1913 Webster]
2. In England, one of the highest order of nobility after princes and princesses of the royal blood and the four archbishops of England and Ireland. [1913 Webster]
3. In some European countries, a sovereign prince, without the title of king. [1913 Webster]
4. pl. The fists; as, put up your dukes. [slang] [PJC]
Duke's coronet. See Illust. of Coronet.
To dine with Duke Humphrey, to go without dinner. See under Dine. [1913 Webster]