night 
(nīt)
(nīt)n.
1.
a. The period between sunset and sunrise, especially the hours of darkness.
b. This period considered as a unit of time: for two nights running.
c. This period considered from its conditions: a rainy night.
2. The period between dusk and midnight of a given day: either late Thursday night or early Friday morning.
3.
a. The period between evening and bedtime.
b. This period considered from its activities: a night at the opera.
c. This period set aside for a specific purpose: Parents' Night at school.
4.
a. The period between bedtime and morning: spent the night at a motel.
b. One's sleep during this period: had a restless night.
5. Nightfall: worked from morning to night.
6. Darkness: vanished into the night.
7.
a. 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).
b. 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).
adj.
1. Of or relating to the night: the night air.
2. Intended for use at night: a night light.
3. Working during the night: the night nurse.
4. Active chiefly at night: night prowlers.
5. Occurring after dark: night baseball.
[Middle English, from Old English niht; see nekw-t- in the Appendix of Indo-European roots.]