1. a principle or condition that customarily governs behavior;
"it was his rule to take a walk before breakfast"
"short haircuts were the regulation"
2. something regarded as a normative example;
"the convention of not naming the main character"
"violence is the rule not the exception"
"his formula for impressing visitors"
3. prescribed guide for conduct or action
4. (linguistics) a rule describing (or prescribing) a linguistic practice
5. a basic generalization that is accepted as true and that can be used as a basis for reasoning or conduct;
"their principles of composition characterized all their works"
6. a rule or law concerning a natural phenomenon or the function of a complex system;
"the principle of the conservation of mass"
"the principle of jet propulsion"
"the right-hand rule for inductive fields"
7. the duration of a monarch's or government's power;
"during the rule of Elizabeth"
8. dominance or power through legal authority;
"France held undisputed dominion over vast areas of Africa"
"the rule of Caesar"
9. directions that define the way a game or sport is to be conducted;
"he knew the rules of chess"
10. any one of a systematic body of regulations defining the way of life of members of a religious order;
"the rule of St. Dominic"
11. (mathematics) a standard procedure for solving a class of mathematical problems;
"he determined the upper bound with Descartes' rule of signs"
"he gave us a general formula for attacking polynomials"
12. measuring stick consisting of a strip of wood or metal or plastic with a straight edge that is used for drawing straight lines and measuring lengths