Definition of metastable in US English:



  • 1(of a state of equilibrium) stable provided it is subjected to no more than small disturbances.

    • ‘At very low membrane tension, small fusion pores can be trapped in a flickering metastable state.’
    • ‘In this mode the upper level is pumped up before the lower level has had time to empty and, consequently, there is no room in the lower levels for the metastable states to decay to.’
    • ‘A local minimum near the transition state in the free energy profile suggests metastable states that are populated with a very low probability at equilibrium.’
    • ‘What allows this metastable state to persist is the existence of an energy barrier.’
    • ‘This disappearance of a metastable state is precisely what happens at a ‘spinodal point’ in equilibrium statistical physics.’
    1. 1.1 (of a substance or particle) theoretically unstable but so long-lived as to be stable for practical purposes.
      • ‘The metastable film melts with no increase in area beyond the thermal expansion of the LE phase.’
      • ‘In van der Waals' theory, the spinodals are the turning points in the loops of the phase diagram where a metastable liquid or gas becomes unstable.’
      • ‘A plasma is an ionised gas containing ions, metastable species, radicals, neutrals and electromagnetic radiation.’
      • ‘Transformation of the monolayers involves a kinetic transition to a metastable state, analogous to the kinetic formation of metastable liquids.’
      • ‘The compressed films are metastable at these pressures.’