noun
middle of the night; dead of night; midnight
Literary or formal word for the deep, quiet hours of the night. Not used in everyday conversation; more common in written descriptions or poetic contexts.
深更の静けさに包まれた街を歩いた。
I walked through the town wrapped in the stillness of the dead of night.
深更まで仕事を続けるのは体に良くない。
Working until the middle of the night is not good for your health.
Compound of 深 (deep) and 更 (late night/watch of the night). The exact historical derivation is uncertain, but the combination naturally conveys the deep, late hours of the night.