A warden's job is to manage a prison — so while she may be uniformed and armed like a guard, her actual tasks may look more like a desk job. The noun warden has traditionally been used to talk about someone in an official supervisory position, especially in British English, but the prison guard definition goes back to the early thirteenth century, when it meant "one who guards." The root is the Old English word weard, "a watchman or sentry."