stationary state

https://doi.org/10.1351/goldbook.S05953
  1. (in quantum mechanics) A state that does not evolve with time.
  2. (in kinetics)
    See: steady state
Source:
PAC, 1994, 66, 1077. 'Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)' on page 1166 (https://doi.org/10.1351/pac199466051077)