Human activity * Business rule, a rule pertaining to the structure or behavior internal to a business * School rule, rules part of school discipline * Sport rule, rule that defines how a sport is played * Game rule, rule that defines how a game is played * Moral, a rule or element of a moral code for guiding choices in human behavior * Norm (philosophy), a kind of sentence or a reason to act, feel or believe * Rule of thumb, a principle with broad application that is not intended to be strictly accurate or reliable for every situation * Unspoken rule, an assumed rule of human behavior that is not voiced or written down
Science
* Norm (sociology), a term in sociology describing explicit or implicit rules used within society or by a group (i.e. social norms) * Rule of inference or transformation rule, a term in logic for a function which takes premises and returns a conclusion * "Rule X" elementary cellular automaton, where X is a number between 0-255 characterizing a specific model (e.g. Rule 110) * Ruler, or "rule"; a distance measuring device
Law and government * Law, which may informally be called a "rule" * Government * Rule of law, government that consists of rule not by one person but by laws, as in a democratic republic; no one person can rule and even top government officials are under and ruled by the law. In addition to this, in such a government, laws cannot be enacted which would undermine the rule of law via the setup of separate frameworks of rules for separate subsets of the population. * Ruler, a monarch, the person who rules a country * Procedural law, a rule set governing the application of laws to cases * Court order, a decision by a court * Military rule, governance by a military body * Monastic rule, a collection of precepts that guides the life of monks or nuns in a religious