noun, noun which may take the genitive case particle 'no', na-adjective
A somewhat literary or poetic word for something that lasts forever or is unchanging. Often used in the phrase とこしえに (eternally).
この愛はとこしえに変わらない。
This love will never change, for all eternity.
とこしえの平和を願う。
I wish for eternal peace.
Derived from classical Japanese 常 (toko, 'eternal') + し (emphatic particle) + へ (direction particle), literally 'toward eternity'. The exact historical development is uncertain.