You’ve probably heard that “the whole nine yards” comes from ammunition belts. Or cement mixers. Or fighter-plane canopies. Here’s the uncomfortable truth: nobody knows. And almost every idiom origin story you’ve heard follows the same pattern—confident, memorable, and almost certainly wrong.
This is for anyone who’s repeated an idiom origin at dinner and wondered if it was actually true. Some of these stories are documented. Some are plausible guesses that became “facts” through repetition. And some are complete mysteries we’ve collectively decided to solve by inventing answers. Learning to tell them apart is more useful than memorizing another false etymology.
1. “Bite the bullet” — Real origin, brutal context
This one’s documented. In the 1840s and 1850s, battlefield surgeons performed amputations without anesthesia. Soldiers bit down on cartridge casings—literally bullets—to manage the pain. The phrase appears in Blackwood’s Edinburgh Magazine in 1847, and it meant exactly what it sounds like.
The reason this origin stuck is that it’s both specific and visceral. You can picture it. Most false idiom origins fail because they’re too vague or too clever. This one succeeds because it’s neither.
2. “The whole nine yards” — Genuinely unknown
This is where idioms come from gets humbling. There are over twenty competing theories for this phrase: cement mixer drums, World War II ammunition belts, fabric bolts, Scottish kilts, burial shrouds. None of them have primary documentation. The earliest recorded use is from the 1950s, which rules out most of the romantic wartime stories.
The truth is we don’t know, and we probably never will. What’s interesting is how uncomfortable that makes people. The human brain dislikes mystery, so we construct plausible stories and repeat them until they feel true. This idiom is a perfect case study in how false etymologies spread.
3. “Caught red-handed” — Legal origins, literal blood
This phrase comes from 14th-century Scottish law. If you were caught with blood on your hands—literally red-handed—you were caught in the act of poaching or murder. The Oxford English Dictionary traces “red-hand” to legal documents from that period, and the logic is straightforward: evidence you can’t deny.
It’s a rare example of an idiom whose meaning hasn’t drifted at all. Caught red-handed still means exactly what it meant seven hundred years ago.
4. “Spill the beans” — Disputed, probably unknowable
The folk story here is ancient Greece: voters dropped beans into jars, and if someone knocked the jar over, the secret vote was revealed. It’s a great story. It’s also unsourced. The earliest English use of “spill the beans” is from the 1920s, and there’s no documented connection to Greek voting practices.
The real origin is probably lost. What we’re left with is a memorable false etymology that’s easier to repeat than “we don’t know.” And once enough people believe it, does it matter? This is where idiom origins explained becomes idiom origins invented.
5. “Break the ice” — Literal, then metaphorical
Before trains and planes, frozen rivers and canals were a real problem. Traders and postal workers had to physically break the ice before travel or commerce could resume. The metaphorical use—breaking social awkwardness to start conversation—appears in English literature by the 1600s.
This is an example of an idiom that preserved its logic even as the literal practice disappeared. You can still picture what breaking ice means, even if you’ve never had to do it to get somewhere.
6. “Raining cats and dogs” — Unknown, despite confident stories
You’ve heard the theories: shipboard animals falling through bilge grates in storms, Norse mythology, thatched roofs harboring animals that fell during heavy rain. None of these have evidence. The earliest written use is from Jonathan Swift’s diary in the 1660s, and he doesn’t explain it.
This is another case where the false stories are more interesting than admitting we don’t know. The thatched-roof theory is especially persistent because it’s specific enough to sound researched. It’s not.
7. “Mad as a March hare” — Observation, not metaphor
Hares actually are more aggressive and erratic in March—it’s mating season. English writers noticed this by the 1500s, and the phrase stuck. This isn’t so much an idiom with a “strange origin” as it is a direct observation that became figurative over time.
The reason this one’s interesting is that it’s one of the few idioms where the original meaning is still visible if you know what to look for. March hares really do act that way.
8. “Throw in the towel” — Boxing, 1890s, literal
In late 19th-century boxing, a cornerman would throw a towel into the ring to signal surrender. The phrase appears in boxing records from the 1890s onward, and the practice was standard enough that the metaphor made immediate sense to audiences.
This is another idiom that hasn’t drifted. Throwing in the towel still means giving up, and the image is still legible even if you’ve never watched a boxing match.
9. “Let the cat out of the bag” — Plausible, unverified
The story: medieval market fraud. You buy a pig in a sack, you get home, you open it, and it’s a cat. The deception is revealed. This story circulates in European folklore by the 1500s, but there’s no documented origin for the English phrase.
It’s plausible. It fits the meaning. But “plausible” and “documented” aren’t the same thing, and this is where weird idiom meanings start to blur with invented explanations. We like the pig-in-a-sack story because it’s concrete, not because it’s proven.
How false origins become “real”
Here’s the pattern: an idiom’s true origin is lost, mundane, or hard to verify. Someone invents a memorable story. That story gets repeated in books, classrooms, and dinner conversations. Eventually, the invented story becomes the “accepted” explanation, even though it’s speculative at best.
The history of English sayings is as much about collective invention as it is about documentation. We’re storytelling animals. When we don’t know why we say something, we make up a reason—and if the reason is good enough, it sticks.
Frequently asked questions
What is the origin of the phrase “bite the bullet”?
Documented from 1840s battlefield surgery. Soldiers bit cartridge casings during amputations without anesthesia. First written reference appears in Blackwood’s Edinburgh Magazine in 1847. This is one of the few idiom origins with clear historical evidence.
Where does “the whole nine yards” come from?
Unknown. Over twenty theories exist—cement mixers, ammunition belts, fabric bolts—but none have primary documentation. Earliest recorded use is from the 1950s. The true origin is likely lost, and confident explanations are speculation.
Why do we say “spill the beans”?
Disputed. The ancient Greece voting story is unsourced folklore. Earliest English use is from the 1920s. The real origin is probably unknowable, which is why the false story persists—it’s more satisfying than admitting uncertainty.
How do idiom meanings change over time?
Folk etymology drives most changes. When an idiom’s origin is forgotten, people invent explanations—and those explanations sometimes shift how the idiom is used. Repetition, cultural moments, and memorable imagery determine which idioms survive and which meanings drift.
Most idiom origins are either boring (observation, literal practice) or lost entirely (speculation, folk myths). The ones that feel “strange” are usually the ones where we’ve replaced uncertainty with a confident guess. If you want to understand where idioms come from, start by getting comfortable with “we don’t know”—it’s the most honest answer for at least half of them. For more on how everyday phrases enter the language, see history of common phrases. And Why Is Friday the 13th Unlucky? explores another case where we’ve collectively embraced a made-up origin.