ETYM French duc, from Latin dux, ducis, leader, commander, from ducere to lead; akin to as. teón to draw; cf. as. heretoga (here army) an army leader, general, German herzog duke. Related to Tue, Doge, Duchess, Ducat, Duct, Adduce, Deduct.
1. A British peer of the highest rank.
2. A nobleman (in various countries) of high rank.
Highest title in the English peerage. It originated in England 1337, when Edward iii created his son Edward, Duke of Cornwall.