have an early/a late night

have a late night

To go to sleep later than one typically does. She must have had a late night last night considering how she yawned all through that meeting.
See also: have, late, night

have an early night

To go to sleep earlier than one typically does. You need to have an early night tonight so that you're rested for your exam tomorrow.
See also: early, have, night

have an early/a late ˈnight

go to bed earlier or later than usual: I’d better have an early night if I want to get up at 6 o’clock.I’ve had a lot of late nights recently.
See also: early, have, late, night