metastable

met·a·sta·ble  (mt-stbl)

adj.

Of, relating to, or being an unstable and transient but relatively long-lived state of a chemical or physical system, as of a supersaturated solution or an excited atom.

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meta·sta·bili·ty (-st-bl-t) n.

Thesaurus

Adj.

1.

metastable - (of physical systems) continuing in its present state of equilibrium unless sufficiently disturbed to pass to a more stable state of equilibrium natural philosophy, physics - the science of matter and energy and their interactions; "his favorite subject was physics"