Where Everyday Phrases Actually Come From
Fifteen common sayings traced to their real origin — and the popular explanations that turn out to be invented, including almost every acronym story you have heard.
Phrase origins attract invented explanations more than almost any other subject. These are the ones that hold up, and a few famous ones that do not.
Genuine origins
Rule of thumb. From using the thumb as a rough measure in brewing, carpentry and cooking. The widely repeated claim that it refers to a law permitting a man to beat his wife with a stick no thicker than his thumb has no legal basis; it comes from an 18th-century joke about a judge, repeated until it sounded official.
Steal someone’s thunder. Precisely traceable. The playwright John Dennis invented a new way of making thunder noises for his 1704 play, which flopped. He then heard his own thunder machine being used in a production of Macbeth and said, "They steal my thunder."
Turn a blind eye. Attributed to Nelson at Copenhagen in 1801, who raised a telescope to his blind eye to avoid seeing the signal to withdraw. The story is probably embroidered but is contemporary rather than invented later.
Bite the bullet. From battlefield surgery before anaesthetic, giving the patient something to clamp down on.
Mad as a hatter. Hat makers used mercury to treat felt. Chronic mercury poisoning causes tremors, slurred speech and severe anxiety, and the trade’s reputation long predates Lewis Carroll.
Caught red-handed. A Scottish legal term from the 15th century, meaning a poacher caught with blood still on the hands.
Pull out all the stops. From organ playing: the stops control which sets of pipes sound, and pulling them all out produces maximum volume.
At loggerheads. A loggerhead was a long-handled iron tool with a ball on the end, used for heating tar — and apparently for hitting people with.
Saved by the bell. Boxing, where the bell ends the round before a count is finished. Not, as commonly claimed, from bells on coffins for the accidentally buried; those devices existed but the phrase does not come from them.
Let the cat out of the bag. Disputed, but most likely from markets where a piglet was sold in a sack and a cat substituted by dishonest traders. Opening the bag revealed the fraud. The same trick gives us "a pig in a poke".
Origins that are invented
Almost every acronym story is false. English made very few words from acronyms before the 20th century. "Posh" does not stand for Port Out, Starboard Home. "Golf" is not Gentlemen Only, Ladies Forbidden. "Tip" is not To Insure Promptness. "News" is not North East West South. Each was reverse-engineered long after the word existed.
Raining cats and dogs has no convincing origin. The story about animals falling through thatched roofs is a 1990s internet invention, part of a widely circulated list of fake etymologies that also produced "the whole nine yards" and "threshold" explanations.
Sleep tight is unlikely to refer to tightening rope beds. The adverb "tight" meaning soundly is attested, and rope beds were not usually tightened nightly.
How to spot a fake
Be suspicious when the explanation is unusually tidy, when it involves an acronym, when it explains the phrase too literally, and when it comes with a vivid historical scene. Real etymologies are usually messier and often uncertain.