A stale joke, story, or saying, as in Dad keeps on telling that old chestnut about how many psychiatrists it takes to change a light bulb. This expression comes from William Dimond's play, The Broken Sword (1816), in which one character keeps repeating the same stories, one of them about a cork tree, and is interrupted each time by another character who says “Chestnut, you mean . . . I have heard you tell the joke twenty-seven times and I am sure it was a chestnut.”