When daily life veers into the unknown and unexpected, people use everyday expressions for explanations and reassurance. Whether employed to bring good luck or prevent bad, to illuminate mysterious things like sleep or assuage the anxiety we feel when announcing our plans to the world, familiar sayings offer comfort through magical “logic” when science and reason cannot. So—fingers crossed!—let’s explore the origins and meanings of six well-known turns of phrase.
Many everyday expressions have superstitious applications—they are spoken aloud to make the mysterious more understandable. And what everyday event presents some of the most enduring mysteries? Sleep. Uncertainty surrounds the source of the expression “Sleep tight.” Its earliest surviving appearance is in the May 2, 1866, journal entry of Southern writer Susan Bradford Eppes: “Goodbye, little Diary. ‘Sleep tight and wake bright,’ for I will need you when I return.” Some say “Sleep tight” dates to American colonial times, when crisscrossed ropes were stretched across bed frames, requiring periodic tightening to support the mattress and ensure a good night’s sleep. Others simply point to the Oxford English Dictionary, where tight is a little-used version of the adverb tightly, meaning “soundly” or “well.”
If we don’t sleep tight, we may wake on the metaphorical “wrong side of the bed.” This idiom appears to stem from an age-old prejudice against the left. In ancient Rome, rising from the bed’s left side was thought to bring misfortune. Modern research shows sleeping on a particular side of the bed does correlate with greater happiness, but counter to folk wisdom, the “right” side of the bed for sleeping is, in fact, the left.
Everyday expressions commonly address misfortune. Whereas today knocking on wood preemptively attempts to keep bad luck at bay, the idea of waking on the wrong side of the bed serves as a counterfactual explanation for ill temper or for woes that have already occurred. But the seemingly more meticulous ancient Romans, hoping to deflect evil spirits and forestall a sinister future, tried to wake up on, step forward with and even sneeze to the right side. The traditional Chinese practice of feng shui—positioning items harmoniously to create positive energy—also encourages rising from a certain side of the bed (the left) to attract invisible forces that bring health, money and power.
Knocking on wood may have originated in pre-Christian religious societies. Celtic druids believed that powerful nature spirits dwelled within trees and that touching the trunks would awaken them. Today we knock on wood to manage our expectations about the future, in an acknowledgment of our ultimate uncertainty when we try, out loud, to describe and take stock of our life. Perhaps we too seek the special attention of invisible forces, just as we knock on a door so someone on the other side will hear us—and answer.
“Knock on wood” and “Fingers crossed” have become quotidian invocations to prevent bad luck (or activate good); in using them, the speaker also adopts the mystical belief that certain words have the power to shape the future. These two charms assert their power vocally, but the gestures that symbolize them are at least equally important. After saying “Knock on wood,” we usually cast about desperately for a nearby door, window frame or other wooden surface to rap our knuckles against. Often the statement is omitted entirely, the gesture being expressive enough.
The same goes for “Fingers crossed,” but when fingers are crossed in silence, the gesture contains another layer of meaning. Children (and immature adults) often cross their fingers while fibbing or making promises they don’t intend to keep—transforming the phrase from a device to ward off adversity into an unspoken message to some higher power that one’s words should not be taken seriously. Considering how many other expressions—“Thumbs up,” “Cross my heart” or the more contemporary “Talk to the hand”—also operate simply as gestures, it’s a safe bet that today’s new popular saying may become tomorrow’s normal, everyday sign language.
Knocking on wood is a ward against bad luck, but telling someone to break a leg paradoxically wishes good luck. Most often used among actors before a performance, “breaking a leg” was once common slang for taking a bow, and a successful show provides many opportunities for actors to curtsey or bend the knee, i.e., “breaking” the line of the leg. One interesting (though apocryphal) theory traces the phrase to Abraham Lincoln’s assassination, when actor John Wilkes Booth leaped from the president’s theater box after shooting and broke his leg as he landed onstage.
“Break a leg!” didn’t appear in print until 1921, however. In “A Defence of Superstition,” author Robert Wilson Lynd attributes it to horse racing and superstitious jockeys: “To wish a man luck when on his way to a race-meeting is considered unlucky. Instead of saying ‘Good luck!’ you should say something insulting, such as ‘May you break your leg!’” Such behavior—like knocking on wood—presumes a higher power is eavesdropping, and the speaker tries to deter or fake out a mischievous divinity. These attempts to avoid a cosmic jinx recall Woody Allen’s admonition that if you want to make God laugh, tell him your plans.
“Break a leg!” and “Bless you!” are exclamatory pleas, the former trying to counteract a meddlesome God and the latter appealing for benediction. Nervous actors who say “Break a leg!” surely need help from above, but why should sneezing require divine intervention? Perhaps because it often precedes sickness. As early as 590 A.D., Pope Gregory the Great commanded his flock to fight disease (in that case, an outbreak of bubonic plague) with constant prayer. The sound of a sneeze was quickly followed by calls for the Almighty to protect the sneezer—though since the germs ejected can travel up to five feet, the person sneezed upon also needs help.
Other superstitions suggest the heart stops—or the soul escapes the body—during a sneeze. Echoes of such ancient ideas surface in the Irish folktale “Master and Man,” when a leprechaun-like character threatens to kidnap a young bride if she sneezes three times without anyone saying “God bless you.” Luckily, the tale’s hero blurts out the required phrase, saving the newlywed. And that’s another impulse behind both “Break a leg!” and “Bless you!”: Whether we wish our friends success or good health, these expressions let us help one another.
Though their origins are uncertain, “Bless you!” and “Fingers crossed” both have ties to early Christianity and the Roman Empire but seem to go back even further. Persecuted Roman Christians intertwined their middle and index fingers to symbolize the holy cross in miniature in order to ward off evil—and likely also to signal one another secretly, avoiding the more conspicuous upper-body sign of the cross. But some trace the gesture back before Christ’s crucifixion to Bronze Age Europeans, who may have linked fingers to sway spirits in their favor.
Saying “Bless you!” to entreat God for a measure of grace was a superstitious response to sneezing well before medieval attempts to defend against evil spirits or sixth-century papal efforts to combat bubonic plague. As early as 77 A.D., Roman historian Pliny the Elder reported the emperor practicing this ritual, and in Roman writer Apuleius’s novel The Golden Ass (150 A.D.), the hero blesses a maiden each time she sneezes. Neither text bothers to explain the practice, implying it was common well before the first century—perhaps another hand-me-down from the ancient Greeks, who (according to Homer) saw sneezes as omens.