(US, law) A common law rule according to which a baseball team cannot be held liable for injuries suffered by a spectator struck by a foul ball so long as the team has offered some protected seating.

(law) A common law rule according to which an ambiguous criminal law should be interpreted in the way most favorable to the defendant.

(law) Synonym of fireman's rule

A formula used to estimate underlying probabilities when there are few observations, or for events that have not been observed to occur at all in (finite) sample data.

(geometry) Pythagorean theorem

(typography) Alternative form of en dash

(typography) Alternative form of em dash

(games) A rule used in certain strategy games for the purpose of fairness, where immediately after the first player's initial move the opposing player may optionally switch, taking over the first player's role and position for the rest of the game.

(Canada, crime, law, politics, constitution, human rights) A rule about how long criminal court cases can take, and when exceeding the determined limit, is considered excessive and violating constitutional rights, and thus the criminal proceedings are summarily terminated with no recourse, and the defendant released. The limit of 18 or 30 months from placing criminal charges to trial is established in the rule.

(linguistics, phonology, Indo-European studies) A rule of the Proto-Indo-European reconstructed language that states that a labiovelar stop (*kʷ, *gʷ, *gʷʰ) dissimilates to an ordinary velar stop (*k, *g, *gʰ) next to the vowel *u or its corresponding glide *w.