Key terms & definitions

An action taken to prevent or reduce the risk of harm; also called a control measure.

An earlier action or decision that can be used to justify similar actions in future.

An earlier action or case used as a model or justification for a later one.

A legal principle established in an earlier court decision that guides, or binds, decisions in later similar cases.

An ethical training commitment that a Buddhist undertakes to guide behaviour and avoid harmful actions.

The slow wobble of Earth's rotational axis, which changes the direction it points and the timing of the seasons relative to Earth's position in its orbit.

An insoluble solid that forms in a liquid during a reaction.

An insoluble solid that forms when two solutions react.

An insoluble solid formed during a reaction in a solution.

Water falling from the atmosphere, including rain, snow and hail.

Water that falls from clouds to the Earth's surface, such as rain, snow or hail.

To form a solid from substances in a solution; early oceans produced solid carbonates that settled as sediments.

Water falling from clouds as rain, snow, sleet or hail.

A reaction in which dissolved substances form an insoluble solid.

A reaction in which dissolved substances react to form an insoluble solid.

How close repeated measurements are to one another.

Repeated results that are close to one another.

The closeness of repeated measurements to one another.

How close repeated measurements are to one another.

A bomb or missile whose guidance system directs it towards a selected target, improving accuracy compared with an unguided weapon.

A weapon whose course can be guided towards a selected target, for example using laser guidance or satellite navigation.

Laboratory testing of a potential drug on cells, tissues and live animals before it is tested in people.

Laboratory testing of a potential medicine using cells, tissues and live animals before it is tested in humans.

The Hollywood period before strict enforcement of the Motion Picture Production Code in 1934. The Code had been introduced in 1930, and other censorship pressures still existed.

A Hollywood film made before strict enforcement of the Motion Picture Production Code, also known as the Hays Code.

Knowledge of an event before it happens; a possibility explored in Priestley’s time plays.

A condition that must be satisfied before an algorithm can work correctly, such as sorted input for binary search.

A loop that tests its condition before executing its body, so the body may execute zero times.

The part of the mind containing information outside current awareness that can readily be brought into consciousness.

The feeding interaction in which one organism, the predator, catches and eats another, the prey.