nonchanging

Nonchanging is an adjective used to describe something that does not undergo change over time, maintaining a constant state, property, or condition within a given context. It denotes stability or invariance relative to a reference frame or period, and is typically used where the absence of temporal variation is important. Although understandable, nonchanging is less common in formal discourse, where unchanging, constant, stable, static, or invariant are preferred.

In science, the notion appears in several ways. In physics, a time-invariant quantity remains the same after shifting time; a system in static equilibrium exhibits nonchanging macroscopic properties. In mathematics, a constant function yields the same output for all inputs, and invariants remain unchanged under a specified transformation; fixed points are elements that do not move under a function. In computing, immutability refers to data or structures that cannot be altered after creation, producing nonchanging values through their lifetimes.

In everyday language, nonchanging emphasizes the absence of change rather than the mechanism maintaining it. It is often replaced by terms that specify the domain of constancy, such as constant temperature, fixed coordinates, or invariant properties.

See also: invariance, constancy, immutability, static, equilibrium, stability.