English definition of “night”
/naɪt/ noun [C, U]
DARK › the time in every 24 hours when it is dark and people usually sleep: I didn't get any sleep last night. It's warm during the day, but it can get quite cold at night. The phone rang in the middle of the night. Did you hear that storm during the night? We stayed up almost all night talking. Tim's working nights this week.
EVENING › the period from the evening to the time when you go to sleep: Did you have a good time last night? Are you doing anything on Friday night?
SAYING THE TIME › used to describe the hours from the evening until just after 12 midnight: They're open from 7 in the morning until 10 o'clock at night.
have an early/a late night › to go to bed early/late: We had a bit of a late night last night.
a night out › an evening spent away from home doing something enjoyable: a night out at the theatre
Good night. › You say 'Good night' to someone who is going to bed: Good night, sleep well. → See also the dead of night/winter