1. The time after sunset and before sunrise while it is dark outside
   "The city lights twinkled in the nighttime sky";
   - night, dark

Derived forms: nighttimes

Type of: period, period of time, time period, time span

Antonym: day

Part of: 24-hour interval, day, mean solar day, solar day, twenty-four hour period, twenty-four hours

Encyclopedia: Nighttime