in Misconceptions

Fallacious yet widespread and documented beliefs courtesy of Wikipedia.
It is frequently rumored that the expression "rule of thumb", which is used to indicate a technique for generating a quick estimate, was originally coined from a law allowing a man to beat his wife with a stick, provided it was not thicker than the width of his thumb. In fact, the origin of this phrase remains uncertain, but the false etymology has been broadly reported in media including The Washington Post (1989), CNN (1993), and Time Magazine (1983).