RULE

RULE.
1. A principle that contributes to the organization and control of a group, activity, system, etc., and has the backing of some kind of authority
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2. In LANGUAGE TEACHING and learning, a formal statement about the use of an aspect of a language, such as REGULAR and IRREGULAR verbs in French. Traditionally, such rules have often been learned by heart. They are both prescriptive and proscriptive. See DESCRIPTIVE AND PRESCRIPTIVE GRAMMAR.

3. In LINGUISTICS, a formal statement of the relationship between structures or units, such as the rules for forming plurals in English. Such rules are intended to be descriptive: explicit statements of how a language works (or may work), representing procedures applied by native speakers without conscious reflection when they talk to each other. It is not always easy to keep the first and second senses of the term distinct from the third sense. See DESCRIPTIVISM AND PRESCRIPTIVISM.

4. In PRINTING, a thin strip of metal or its equivalent, used for printing a solid or decorative line or lines. Such a line the length of an em is an em rule, of an en, an en rule; such rules are used in punctuation as longer or shorter DASHES.