Usually said in a situation when the rule is incorrect and unusable.

(law, investment) A standard for the duty of a fiduciary with responsibility over investments.

(law, singular only) The rule that prevents a testator or other transferor of property from controlling further transfer of his property more than twenty-one years after the death of anyone alive at the time of the original transfer who may have some interest in the transfer.

a rule of thumb by which a driver may maintain a safe following distance, allowing at least a two second interval behind any vehicle that is directly in front of the driver's vehicle.

(law) The obligation of a barrister (in certain jurisdictions) to accept any work in a field in which they profess themselves competent to practise, at a court at which they normally appear, and at their usual rates.

A common mnemonic for understanding notation conventions for vectors in three dimensions. / (logic) The systematic use of right-hand turnings to solve a maze.

(idiomatic) Examine carefully and thoroughly.

(law) A legal principle that holds an original copy of a document as superior evidence.

(soccer) The prohibition of teammates closer to the opponents' goal than the person kicking or throwing the ball unless there are three opponents at least as close to their goal line.

To rule with stern severity.