# 11th commandment

idiom

Source: https://englishreference.com/idiom/11th-commandment
Updated: 2026-08-10

## Meaning

A well-known convention (often the most well-known of a certain field) which supposedly can not or should not be broken.

## Examples

- 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.

## Origin

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.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.