Rule

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
Monasticism, or Monastic Rule, the document giving the way of life to be led by the members of the varying Religious Orders in the Catholic Church and other Christian groups which follow a monastic way of life
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

Norm (social), 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
Phrase structure rule or rewrite rule, used in some theories of linguistics
"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
Phonological rule

Law, which may informally be called a "rule"
Government
Rule of law, government based not on arbitrary decisions of officials but on laws
Procedural law, a ruleset 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 order
In rulemaking by the federal government of the United States, a regulation mandated by Congress, but written or expanded upon by the executive branch
Rulers.org, a website containing lists of heads of state and government
Advance tax ruling, a tool for conforming taxation arrangements

Ja Rule (born 1976), hip hop artist
- R.U.L.E., a 2005 greatest hits album by Ja Rule
"Rule" (song), a 2001 song by rapper Nas
Rule, an album by Japanese rock singer Anna Tsuchiya
"Rule/Sparkle", a 2009 song by Ayumi Hamasaki
Rules (album), a 2009 album by the band The Whitest Boy Alive
"Rules" (song), a 1996 KMFDM song
"Rules" (Shakira song), a 2001 Shakira song on her album Laundry Service
Rules: Pyaar Ka Superhit Formula, a 2003 Bollywood film