donkey [L18th] Before the late 18th century a donkey was an *ass. At first the word donkey was used only in slang and dialect, and its origin is lost. Early references indicate that it rhymed with *monkey, and this has prompted some to suggest that it comes from the colour dun [OE] or from the man’s name Duncan. The expression for donkey’s years [E20th], ‘for a very long time’, is a pun referring to the length of a donkey’s ears and playing on an old pronunciation of ears which was the same as that of years. The British expression yonks [M20th], with the same meaning, may derive from it. See also easel at dutch words.