Fan mail from some flounder.
Dear Word Detective: Recently one of our four giant cats (all Maine Coons) showed me he’s figured out how to undo a mechanical latch on a little decorative box we have in our hearth room. I wondered to myself if it was a fluke, or whether it’s just a matter of time before they figure out the can opener, and I should start watching my back. Which leads me to: when did “fluke” start to mean “by random chance” instead of what I presume was the original usage (fin-like)? — Christopher Schultz.
Good question, but I should warn you about your cat. He didn’t “show” you that he’d learned to work that latch. You simply caught him at it. Many cats know all sorts of things but pretend to be clueless because it gives them a tactical advantage. For instance, I happen to know that our cat Gus can open a door by turning the doorknob. I’ve seen him do it from the next room. But he never does it when he knows I’m watching. I just wish he’d close the closet door when he’s done in there.
The connection between “fluke” in the sense of “fin” and “fluke” meaning “a lucky accident” is easy to explain. There is no connection, and the two words, as far as anyone has been able to determine, are completely unrelated. There are actually three separate “flukes” in English: a kind of flatfish similar to the flounder, the triangular pointy things on the end of each arm of an anchor, and the “dumb luck” demonstrated by your cat.
Of the three types of “fluke,” the flatfish is the easiest to explain. “Fluke” in this sense is drawn from the Old Norse word for the critter, “floke,” which in turn is related to Germanic roots meaning “flat,” which flukes and flounders certainly are. Those same Germanic roots also produced “flake” and the word “flat” itself.
The origin of the “triangular plate at the tip of an anchor” kind of “fluke,” which first appeared in the 16th century, is a mystery. Some authorities, however, believe it is derived from the “flatfish” sense of “fluke,” perhaps because of a resemblance between the flatness of the fish and the anchor tips. This seems entirely reasonable to me, especially since both words sprang from the world of seafaring. The use of “fluke” to mean “one of the two parts of a whale’s triangular tail” (or simply “fin” in a looser sense) comes from the resemblance of the tail to the pointed tips of an anchor.
That leaves the “lucky accident” sense of “fluke” to explain. We do know for a fact that “fluke” in this sense was originally a billiards term meaning “a lucky shot,” and first appeared in the mid-1800s. Unfortunately, no one has ever been able to pin down the exact origin of this “fluke,” although within a few years after its first appearance it was being used outside the billiards hall to mean simply “a stroke of good luck” (“Whose run-away horse he had stopped …by the merest fluke,” 1889), and soon after was even used to mean “a sudden gust of wind.” The best theory so far about the origin of this “fluke” traces it to an old English dialect word “fluke” meaning “guess.” It may never be possible to definitively prove this source, but it seems a small jump from meaning “guess” to “lucky shot,” and I’d say that dialect word is almost certainly the source of this kind of “fluke.”