Someone who never appears to age. In his novel, The Picture of Dorian Gray, Oscar Wilde told the story of the title character who made a Faustian arrangement with an artist to paint his portrait, the proviso being that Gray would not age, but the face in his painting would. As with such pacts, Gray lived to rue it. It didn't take long before “Dorian Gray” was applied to anyone who showed no signs of aging. If, for example, after ten or twenty years you met a long-lost friend who looked much the same as when you last saw him or her, you would acknowledge that miracle as “Hey, it's Dorian Gray.” And if your friend recognized the allusion, the reply was likely to be, “Yeah, but you should see the painting in my attic.”

The passage of time. A folk song attributed to Stephen Foster and supposedly referring to a 19th-century harness-racing horse named Lady Suffolk begins, “Oh, the old gray mare, she ain't what she used to be . . . Many long years ago.” Unkind people used the image to refer women “of a certain age” (or older), although when used by themselves about themselves, it has an air of self-deprecating resignation. For example, a middle-aged woman who leaves the dance floor short of breath after a vigorous jitterbug may wipe her brow, reach for a cold drink, and exclaim, “The old gray mare ain't what she used to be.”