约定俗成

• Pinyin: yuē dìng sú chéng
• Hanzi breakdown: 约 = 纟 + 勺 (silk/thread + ladle — to bind, to agree/constrain); 定 = 宀 + 正 (roof + upright — to settle, fix firmly); 俗 = 亻 + 谷 (person + valley — what ordinary people share in common, custom); 成 = 戊 + 丁 (ancient weapon forms — to accomplish, to form/become)

Meaning

Established by common convention; accepted through habitual social practice over time. Said of names, norms, or customs that have acquired legitimacy through shared usage rather than formal decree.

A four-character idiom (成语) originating in the philosophical text 荀子·正名 (Xunzi, Chapter on Rectifying Names). It describes how names, terms, customs, and conventions acquire social validity and normative force through habitual collective practice rather than top-down imposition. Frequently invoked in discussions of language evolution, legal custom, cultural norms, and social conventions. 语言是约定俗成的 (language is conventionally established) is a canonical application of this concept.

Examples

1. 语言符号和所指对象的联系，往往不是天然的，而是约定俗成的结果。 The link between linguistic signs and what they refer to is often not natural, but the result of convention.
2. 在法学中，习惯法之所以有效，也与约定俗成有关，因为长期实践会形成规范预期。 In law, customary law is effective partly because of convention, since long practice creates normative expectations.
3. 许多被视为天经地义的规范，其实都是约定俗成的产物，带有鲜明的历史条件。 Many norms seen as self-evident are actually products of convention and carry clear historical conditions.

Usage Guide

Context: linguistics, law, culture, social analysis, philosophy, education

Tone: analytical

Do Say

• 简化汉字的争论里，双方都借约定俗成立论，只是一个看重普及后的习惯，一个看重繁体传统。(In the debate over simplified Chinese characters, both sides appealed to convention, but one valued habits formed through widespread use while the other valued the long traditional script.)
• 法律术语的含义常在司法实践中约定俗成，因此理解它们不能只看字面，还要看判例传统。(The meanings of legal terms are often conventionally formed in judicial practice, so understanding them requires more than the literal meaning; it also requires knowing case-law tradition.)

Don't Say

• 他的坏习惯已经约定俗成了 — 约定俗成 refers to social conventions or norms that have formed through collective practice in a community and carry shared normative legitimacy; it does not describe personal habits or private behaviours, however entrenched; for a personal habit use 积习难改 or 习以为常; applying 约定俗成 to individual behaviour misunderstands its inherently collective and normative dimension

Origin & History

约定 (agreed upon/settled — 约 to bind/agree, from 纟thread + 勺 ladle-like stroke + 定 to settle/fix firmly) + 俗成 (formed by custom — 俗 folk custom/everyday convention + 成 to become/form). Together: that which has been settled and formed through folk convention and common agreement over time.

Cultural Context

Era: Classical — Warring States; ongoing relevance

Generation: All ages

Social background: Universal