nonequi

Nonequi is an informal term sometimes used in science and engineering to refer to phenomena or systems that are not in thermodynamic equilibrium. It functions as a shorthand rather than a formal technical designation, appearing in lecture notes, blogs, and some papers to streamline discussion of non-equilibrium behavior.

Etymology and usage

The word blends nonequilibrium and its common abbreviation, nonequi, and is most often encountered in discussions of dynamic processes where external driving forces, dissipation, or continuous fluxes prevent a system from reaching equilibrium. Because it is not a standardized term, its meaning can vary by author, context, and discipline, but it generally signals a focus on time-dependent or out-of-equilibrium aspects rather than static, equilibrium properties.

Concepts and scope

When nonequi is used, it typically signals topics such as transient dynamics, relaxation toward equilibrium, or sustained non-equilibrium steady states. It may encompass areas like non-equilibrium thermodynamics, irreversible processes, kinetic theories, and dissipative structures. In practice, nonequi discussions emphasize how external perturbations, energy exchange with surroundings, or intrinsic drive alter system behavior in ways that equilibrium models cannot capture.

Domains and examples

Nonequi appears in discussions of chemical kinetics under constant flux, driven granular media, active matter, ecological systems subject to perturbations, and other complex systems where time dependence and external forcing are essential. In rigorous treatment, specialists prefer precise terminology (for example, non-equilibrium thermodynamics or NEGF methods) to avoid ambiguity, but nonequi remains useful as a colloquial shorthand in informal or introductory materials.

See also

Equilibrium; non-equilibrium thermodynamics; irreversible thermodynamics; dissipative systems; steady state.