the small hours

Từ điển Oxford Advanced Learner 8th

the ˈsmall/ˈearly hours idiom
(also the wee small ˈhours ScotE, NAmE also the wee ˈhours)the period of time very early in the morning, soon after midnight
•We worked well into the small hours.
•The fighting began in the early hours of Saturday morning.
Main entry: ↑hour_idiom