Middle Of The Night
Late At Night
noun
The deep night is the middle of the night. It doesn't get any deeper than that before you start coming out of the night to start the next day.
しんや
This is a jukugo word, which usually means on'yomi readings from the kanji. If you know the readings of your kanji you'll know how to read this as well.
こんな深夜に、どうしたの？
What's up this late at night?
深夜に小ばらが空いてきた。
I got a bit hungry in the middle of the night.
環境難民となった熊たちは、新しい国で食べ物を探すため、深夜、国境を越えた。
The environmental refugee bears crossed the border late in the night to find something to eat in a new country.