Day

day user:Alex1011, CC BY-SA 3.0

Unit of time lasting 24 hours, derived from the period of Earth's rotation about its axis

A day is the time period of a full rotation of the Earth with respect to the Sun. On average, this is 24 hours. As a day passes at a given location it experiences morning, afternoon, evening, and night. This daily cycle drives circadian rhythms in many organisms, which are vital to many life processes.

Also known as...days and Earth day