Stationäre

Stationære is a Nordic-language term used to denote the idea of being stationary or not moving. In Danish and Norwegian, forms of the adjective appear as stationær (singular) and stationære (plural), reflecting gender and number. The term is cognate with the English word stationary and is used across scientific and technical contexts to indicate invariance over time or lack of motion.

In science, stationary concepts appear in several fields. A stationary state in quantum mechanics is a state with a time‑independent probability density. In stochastic processes, a stationary process has statistical properties that do not change when shifted in time, often meaning a constant mean and a time‑invariant autocovariance. In chemistry and chromatography, a stationary phase is the part of a system that remains fixed while a mobile phase flows over it to separate components.

In mathematics and statistics, a stationary point is a location where the derivative or gradient vanishes, used to identify potential maxima, minima, or saddle points in a function. In dynamical systems, a stationary (or equilibrium) solution is one that does not evolve with time.

In everyday language and applied fields, stationary describes objects or measurements that do not move or change during a given period. Examples include a stationary object, a camera kept stationary for a shot, or data assumed to be stationary for certain analytical methods.

Etymology stems from Latin statio, meaning a standing place, with the term spreading through European languages. The core idea across uses is invariance in time or lack of motion.