na-adjective, noun which may take the genitive case particle 'no', noun
Describes a state or process that is constant, unchanging, or in equilibrium. Often used in technical contexts such as physics, engineering, and economics (e.g., 定常状態 'steady state').
このシステムは定常状態に達した。
This system has reached a steady state.
定常的な収入がなければローンは組めない。
You cannot get a loan without a regular income.
Compound of 定 (てい, 'fixed, determined') and 常 (じょう, 'usual, constant'). The exact historical derivation is uncertain, but the combination naturally yields the meaning 'regular, stationary'.