last night; the previous night
Refers to the night before a reference point, often in narrative or formal contexts. Can be used adverbially with に.
The previous night, he stayed up late.
出発の前夜に荷造りを済ませた。
I finished packing the night before departure.
eve; night before (an event)
Used for the night before a special day, festival, or major event, such as Christmas Eve or New Year's Eve.
クリスマス前夜に教会へ行った。
I went to church on Christmas Eve.
祭りの前夜、町は静かだった。
The night before the festival, the town was quiet.
The night before the election, the town was quiet.
He was too nervous to sleep the night before the exam.