Dukes/duke it out

Dukes is American boxing and street fighting slang for fists, dates from the mid-19th century and gives rise to the expression ‘put up your dukes’, which is a challenge to start a bout of fisticuffs. The origin is unknown although some sources maintain that it derives from immigrant rhyming slang, Duke of York/fork. Fork was slang for hands with the fingers representing the prongs of a fork. This linkage, however, remains tenuous, especially as very few American expressions derive from rhyming slang. Duke it out meaning to fight it out was first cited from the 1960s and has retained its popularity, especially in political or sporting contests, not necessarily related to boxing.