To substantially control a school administratively, financially, or in terms of its curriculum.

The regulation requiring all traffic (travelling on a road or otherwise) to keep either to the left or the right. / (nautical) A regulation concerning safe handling of vessels on seaways.

(logic) Any of a set of rules used to construct well-formed formulas of a formal language.

(sports) A rule requiring that a player receive medical attention before continuing to play if he is bleeding or there is blood on him or his clothes.

(statistics, singular only) Synonym of the 68-95-99.7 rule

(Internet slang, fandom slang, informal) The proposition that it is possible to find genderswapped versions of every fictional character, especially as fan art on the internet.

(logic, proof theory) A rule for combining (or modifying) well-formed formulas of a formal language in a truth-preserving manner (to yield new well-formed formulas).

(Internet slang, fandom slang, informal) The proposition that there are pornographic depictions of anything and everything, especially as fan art on the Internet.

A doctrine in antitrust law which applies to contracts which "unreasonably" inhibit trade.

(law) A notion of what should "count" as law.