厘定 (lí dìng) is a formal, written verb meaning 'to formulate precisely' or 'to draw up (official documents, standards, or regulations)'. The character 厘 (lí) originally meant 'a unit of weight (1/1000 of a gram)' and carries the extended sense of 'fine measurement' or 'careful distinction'; 定 (dìng) means 'to fix', 'to establish', or 'to decide'. Together, they convey the idea of carefully defining, specifying, or codifying something with precision—especially in legal, administrative, technical, or policy contexts.

This word is rarely used in casual speech. It appears most often in official announcements, government documents, academic writing, or corporate compliance materials—for example, when authorities set boundaries, standardize procedures, or finalize regulatory frameworks. It implies authority, deliberation, and finality, and is almost always followed by an object such as 法规 (regulations), 标准 (standards), 范围 (scope), or 权限 (authority).