The period between dusk and midnight of a given day: either late Thursday night or early Friday morning.
This period considered from its activities: a night at the opera.
The period between sunset and sunrise, especially the hours of darkness.
This period considered as a unit of time: for two nights running.
This period considered from its conditions: a rainy night.
The period between evening and bedtime.
This period set aside for a specific purpose: Parents' Night at school.
The period between bedtime and morning: spent the night at a motel.
One's sleep during this period: had a restless night.
Nightfall: worked from morning to night.
Darkness: vanished into the night.
A time or condition of gloom, obscurity, ignorance, or despair: "In a real dark night of the soul it is always three o'clock in the morning” ( F. Scott Fitzgerald).
A time or condition marked by absence of moral or ethical values: "He never would have let us go untroubled into the night of private greed” ( Anthony Lewis).