critical pointcritical point
the physical condition, specified by pressure or density, at which a substance at its critical temperature can exist as a liquid and vapor in equilibrium
- Physics The temperature and pressure at which the liquid and gaseous phases of a pure stable substance become identical. Also called critical state.
- Mathematics A value in the domain of a given function at which the function has a derivative of zero or a derivative that does not exist. For example, 1 is a critical point for the function x2 − 2x and 0 is a critical point for the function | × |.
(plural critical points)
- (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.
- (mathematics) A maximum, minimum or point of inflection on a curve; a point at which the derivative of a function is zero or undefined.
- A juncture at which time a critical decision must be made.