Although both denote the unnecessary use of words, a "tautology" (from the Greek tautologos, "the same word") is not quite the same thing as a "pleonasm" (from the Greek pleonasmos, "an excess"). Tautology involves saying precisely the same thing twice—"a one-off, unique object"—and is as vital to logic as it is redundant in everyday speech. Pleonasm, however, is a more nebulous species of superfluity: a verbal sin that, often, we may not even be aware we're committing.
In Bruce Chatwin's The Songlines, for example, one character scolds another for daring to talk about "pastoral nomads." The phrase is a pleonasm, he explains, because the word "nomad" derives from the Greek nomos, "a pasture." Similarly, there's Tony Blair's description of the media as "feral beasts," which literally means "wild-animal-like wild animals"—the word "feral" simply derives from the Latin fera, "a wild creature."
Best of all are place names, within which millennia of unwitting repetition can accrue. Northeast Lancashire boasts one Pendle hill: a moniker that combines the old Cumbric word pen with a corruption of the Old English word hyll and the modern English hill to give us, literally, "Hill-hill-hill." It's a phenomenon that offers a virtual archaeology of words whose meanings have drained away into obscurity. A starker version can be found in the colonial misunderstandings that produced, among other things, Lake Nyasa in Malawi ( nyasa being the local word for "lake") and Lake Tahoe in Nevada/California (another "lake lake"). Here, at least, fiction has had its revenge on life, and the title for wittiest place name must surely go to Terry Pratchett's Mount Oolskunrahod—which translates "who is this fool who does not know what a mountain is?"
