1. at night 在夜里
通常的“在夜里”泛指。
These animals only come out at night .
这些动物只在夜晚出来。
They sleep by day and hunt by night .
他们白天睡觉，夜晚捕猎。（有时也用by）
特指在某一天的夜里：
The accident happened on Friday night.
事故发生在星期五夜里。
on the night of 10 January/January 10
在1月10日晚上
Did you hear the storm last night ?
昨天夜里下大雨，你听见了吗？
Let's go out on Saturday night .
我们星期六晚上出去吧。
2. 在午夜12点= at 12:00 midnight
She stole out of the house at midnight.
她在半夜悄悄离开了家。
《21世纪大英汉词典》
They started off to Normandie at midnight.
他们在午夜踏上了开赴诺曼底的征程。
They arrived in Beijing at midnight and checked into Beijing Hotel.
他们于午夜抵达北京并登记住进北京饭店。
at noon 在中午
3. 其他用法
The hotel costs €65 per person per night .
住这家酒店，每人每天要65欧元。
the night train/boat/flight
夜间列车 / 轮船 / 飞机班次
Night fell (= it became dark) .
夜幕降临。
I saw her in town the other night (= a few nights ago) .
前两天晚上我在城里见过她。
the first/opening night (= of a play, film/movie, etc.)
首映 / 首演之夜
The first night crowd packed the building.
第一个夜场演出爆满。
《柯林斯高阶英汉双解学习词典》
a karaoke night
卡拉OK之夜
an Irish/ a Scottish, etc. night (= with Irish/Scottish music, entertainment, etc.)
一场爱尔兰、苏格兰等歌舞晚会
have an early/a late night
比平时睡得早 / 晚；早 / 晚睡
I've had a hell of a day, and all I want is an early night.
这一天糟透了，我就想早点上床睡觉。
have a good/bad night
夜里睡得很好 / 很糟
She talks about him morning, noon and night.
她整天把他挂在嘴边。
election night
选举之夜
wedding night
新婚之夜
