11th commandment
A well-known convention (often the most well-known of a certain field) which supposedly can not or should not be broken.
Meaning adapted from Wiktionary, available under CC BY-SA 4.0.
“In this office, silence is the 11th commandment.”
“In our family, arriving on time for Sunday dinner is the 11th commandment.”
“He ignored the 11th commandment of the industry by speaking openly about the company's secret financial problems.”
“Many professional chefs believe that never using pre-ground pepper is the 11th commandment of a high-end kitchen.”
“The veteran journalist reminded the intern that protecting a source's identity is the 11th commandment of their profession.”
“Although the team claimed to value innovation, they treated the founder's original design philosophy as an 11th commandment that no one dared to challenge.”
The term is a secular extension of the biblical Ten Commandments, first recorded as an addition to the original decalogue. It conveys the implication that a particular social convention or practical rule carries a weight of importance equal to the divine mandates, suggesting that its violation would be a transgression of the highest order.
Last updated August 10, 2026