夜前 is read as やぜん (yazen) and means last night.
やぜん
yazen
よあけまえがいちばんくらい
it's always darkest before the dawn
ぜんや
last night
ぜんやさい
event held the night before another event
ぜんやしき
wake
よ
dinner
やこう
night train
やかん
night
よなか
middle of the night
よあけ
dawn
よぞら
night sky
やがく
night study
よわ
midnight