(physics) the milky turbidity observed in a fluid as it is slowly cooled to just above its critical point, at which point two clear phases (gas and liquid) form

(thermodynamics) The temperature and pressure at which the vapour density of the gas and liquid phases of a fluid are equal, at which point there is no difference between gas and liquid.

(physics) The amount of fissile material needed to support a self-sustaining nuclear chain reaction. / (figuratively) The tipping point.

(mathematics) Any function, in the calculus of variations, that satisfies the Euler equations

The examination and critique of society and literature, drawing from knowledge across social science and the humanities.

(philosophy) The proposition that scientific theories, and any other claims to knowledge, can and should be rationally criticized, and, if they have empirical content, can and should be subjected to tests which may falsify them.

(physics) The angle of incidence beyond which light traveling through a medium experiences total internal reflection upon encountering a boundary with a less refractive medium.

plural of critical angle

Of a system: capable of causing death if it fails or malfunctions.

Of a system: capable of causing serious injury or damage if it fails or malfunctions.