Any scientific principle that expresses various reciprocal relationships for the behaviour of a physical system.

Any of the six recommendations that arose from an investigation of decommissioning of weapons in Northern Ireland in 1996, urging all parties involved in the conflict to renounce violence and agree to disarmament before entering into all-party negotiations.

plural of pigeonhole principle

The practice in fiction, such as in film and television series, of including only one woman in an otherwise male ensemble.

A geometric rule that describes the orientation of the plane of focus of an optical system (such as a camera) when the lens plane is not parallel to the image plane.

(philosophy, rhetoric) The principle according to which an argument should be evaluated in light of its best, strongest possible interpretation.

(cryptography) The idea that a cryptosystem should be designed to be secure even if everything about the system, except the secret key, is public knowledge.

(sociolinguistics) The idea that listeners and speakers need to cooperate in order to communicate effectively.

plural of agreement in principle

A basic, foundational proposition or assumption that cannot be deduced from any other proposition or assumption.