An unstable but potentially long-lived state of a system; for example, a supersaturated solution or an excited atom.

(physics) A metastable isomer / (statistical mechanics) A probability measure on the space of all thermodynamic states of a system

plural of metastate

(physics, chemistry) Of or pertaining to a physical or chemical state that is relatively long-lived, but may decay to a lower energy state when slightly perturbed or through a quantum transition.

A particle, etc. in the metastable state.

In a metastable way.

plural of metastability

plural of metastable

(physics) An excited state of an isotope, often having different a spin quantum number (designated with an m)

plural of metastable isomer