A day (symbol: d) is a unit of time equivalent to 24 hours. It is not an SI unit but it is accepted for use with SI. The SI unit of time is the second. The term comes from the Old English dæg.
Night or nighttime is the period of time when the sun is below the horizon. The opposite of night is day (or "daytime" to distinguish it from "day" as used for a 24-hour period). Time of day varies based on factors such as season, latitude, longitude and timezone.
This suggestion is sent by a person who respects this web site ![]()