Rule of Thumb
"A broadly practical, approximate method or guideline rather than an exact, tested rule."
The genuine, documented origin is refreshingly simple: the top joint of an adult thumb is roughly an inch long, and tradesmen used it for centuries as a rough-and-ready measuring tool when no ruler was handy. The phrase is recorded from 1692 in exactly that practical sense. A much darker explanation began circulating widely in the 1970s and 80s, claiming English common law once permitted a husband to beat his wife with a stick no wider than his thumb. No such law, and no genuine record of any judge ever ruling that, has ever been found.
Myth vs. FactThe wife-beating law story is widely believed and often stated as historical fact, but it traces back to an unverified rumour about an 18th-century judge, satirised in an unflattering 1782 cartoon, and only became attached to the phrase itself in the 1970s. No legal record supports it.
Sources: Oxford English Dictionary (measurement sense recorded from 1692); wife-beating myth traced and debunked in legal-history research including Henry Ansgar Kelly's work for the Journal of Legal Education.
Quick react
Discuss
New comments are held for a quick check before they show up here.
Loading comments…