Refers to the dim light at dawn or dusk, or any faint, subdued light. Often used in literary or descriptive contexts.
In the twilight, the streetlights glowed dimly.
洞窟の奥には薄明だけが差し込んでいた。
Only a faint light reached the depths of the cave.
astronomical twilight
civil twilight
nautical twilight
crepuscular rays; sunbeams
crepuscular
Compound of 薄 (usu-, 'faint') and 明 (mei, 'light'). The exact historical derivation is uncertain, but the word has been used since classical Japanese to describe dim or twilight illumination.