middle of the night; dead of night
夜半に犬の声で目が覚めた。
I was woken by a dog's bark in the middle of the night.
夜半を過ぎても宴会は続いていた。
The banquet went on well past midnight.
夜半になってようやく長い交渉が決着を見た。
It was past midnight before the long negotiations finally reached a conclusion.