The phrase 'rule of thumb' originated from an old law allowing men to beat their wives with a stick no thicker than their thumb.
No such law ever existed in English common law or any documented legal tradition. This urban legend likely emerged in the 1970s-80s during domestic violence awareness campaigns that may have confused metaphorical language with actual statute. The phrase 'rule of thumb' actually traces to practical craft and cooking contexts where rough measurements were made using a thumb's width, brewers, tailors, and cooks relied on thumb-widths as standardized approximations before modern tools. The Oxford English Dictionary's earliest citation (1651) refers to such practical measurements, and no legal codex has ever been found supporting the abuse narrative.
Reception
Sources
- Oxford English Dictionary - Rule of Thumb PRIMARY
- Snopes - Rule of Thumb Beating Wives Myth REFERENCE
- Christine Ammer - Fighting Words REFERENCE