Have you ever been in a conversation when someone remarks, “I’ve never had a toothache — knock on wood,” or “I’ve never gotten a speeding ticket — knock on wood”? We understand these phrases immediately, even though they aren’t literal. They’re idioms — expressions whose meanings come from tradition rather than logic. But where did these familiar sayings actually come from?
A popular explanation for knock on wood takes us back to ancient pagan beliefs. People once thought benevolent spirits lived inside trees. Knocking on the wood would summon these spirits for protection and good luck, keeping misfortune at bay. The simple gesture remains with us centuries later.
Another expression with an interesting history is turn a blind eye. Today, it means to intentionally ignore something wrong. In 1801, during the Battle of Copenhagen, Admiral Horatio Nelson — blind in one eye — was ordered to withdraw. Orders were signaled by flags between ships. Not wanting to retreat, Nelson lifted his spyglass to his blind eye and declared he “saw no signal.” His defiance helped the British defeat the Danish fleet — and gave us a lasting phrase.
Barking up the wrong tree may sound strange, but its roots are quite literal. In 19th-century America, hunting dogs chased raccoons into trees, barking to reveal the animal’s location. But wily raccoons often leapt from one tree to the next, leaving dogs barking at an empty trunk. Thus, the phrase came to mean being mistaken or misdirected.
We also know the nighttime rhyme Sleep tight, don’t let the bedbugs bite. One theory traces it to early American travel by stagecoach or Conestoga wagon. Roadside inns provided beds made of straw mattresses held up by ropes threaded through the frame. When the ropes loosened, they needed tightening to ensure a “tight” sleep. And of course, with straw came bugs — sometimes biting ones.
Not all familiar sayings are idioms. When someone sneezes, we say “Bless You” — a custom possibly dating to 14th-century Europe during the Bubonic Plague. Sneezing was a dangerous early symptom. “Bless You” became a desperate wish for health and protection.
Another popular expression is the whole nine yards. While several theories exist, one explanation shared by a tour guide at the National Museum of WWII Aviation in Colorado Springs ties it to fighter aircraft. Belts of ammunition feeding the plane’s guns stretched nine yards in length. When all bullets were fired, the pilot had truly given “the whole nine yards” — leaving nothing else to offer.
From battles to bedtime, superstition to hunting tales, our everyday language is full of hidden history. Perhaps this is just the beginning — many more phrases we casually use have surprising stories waiting to be told.
