Whenever the government announces the failure of another bank, a news outlet somewhere reports that the bank has “floundered.”

Well it did “flounder,” but once the government seized it, it stopped “floundering” and started “foundering.”

“Flounder” and ”founder” have very similar spellings and meanings, so it’s no wonder that so many people confuse them.

Historically, to “flounder” has meant “to move about awkwardly”; “thrash about”; “become mired.” You’re clumsy, perhaps stuck in quicksand, but you’re still fighting. To “founder” means “to sink” or “to collapse.” The word is often used in a nautical sense: the Oxford English Dictionary traces it to a verb meaning “plunge to the bottom, submerge.”

Many people have used mnemonic devices to differentiate them. One is that when the “floundering” is over, the ship goes to “’ell.” Another utilized the image of a flopping “flounder,” those fish with both eyes on the same side. If you are too engrossed watching that “flounder” flop around on the deck, your boat might strike the rocks and then “founder.” (In which case, the “flounder” goes free and you are very wet.)

In other words, something “flounders” before it “founders.”

But over the years the definitions have been cross-contaminated. Under “founder,” Webster’s New World College Dictionary, used by many journalists, includes “to fill with water, as during a storm, and sink: said of a ship or boat” and “to break down; collapse; fail.” But its first (and thus earliest) definition is “to become stuck as in soft ground; bog down.” That last one sounds more like “floundering” than “foundering” to many.

Under “floundering,” WNW lists only “to struggle awkwardly to move, as in deep mud or snow; plunge about in a stumbling manner” and “to speak or act in an awkward, confused manner, with hesitation and frequent mistakes.”

Other dictionaries “flounder” less. All the definitions for “founder” in The American Heritage Dictionary of the English Language imply a collapse; the closest to “floundering” those definitions come are “to stumble, especially to stumble and go lame” and “to cave in; sink.” It acknowledges the confusion, though, in a usage note with “flounder”: “If John is foundering in Chemistry 1, he had better drop the course; if he is floundering, he may yet pull through.”

Garner’s Modern American Usage says that both “flounder” and “founder” mean failure, but to different degrees: “To flounder is to struggle and plunge as if in mud (not, in other words, to fail completely).”

If all this is making you flop about wondering which to use, go fish.

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Merrill Perlman managed copy desks across the newsroom at The New York Times, where she worked for 25 years. Follow her on Twitter at @meperl.