'(1874), now mainly in put up your dukes (phrase from 1859), probably not connected to duke. Chapman ["Dictionary of American Slang"] suggests Romany dook "the hand as read in palmistry, one's fate" but Partridge ["Slang To-day and Yesterday"] gives it a plausible, if elaborate, etymology as a contraction of Duke of Yorks, rhyming slang for forks, a Cockney term for "fingers," thus "hands."'www.etymonline.com
