dark of the night; deepest night
A poetic or literary expression for the darkest, stillest part of the night, often evoking a sense of depth or abyss.
In the depths of the night, the stars shone especially bright.
He kept walking alone through the dark of the night.
A compound of 夜 (night) + の (possessive particle) + 底 (bottom, depths). The phrase metaphorically likens the darkest part of the night to a deep abyss.