Day or night the day, phrase of the time alternately move the bricks, the Earth is according to the source, the course uses and definitions there are many different and videos, most of its application in solar days, fulfilling the periodicity relative to the sun (day True) is that with the adjustment, it is based on a metric time (seconds) as a period of 24 hours (average day) unit of time, and sometimes a number. The other is, day season is that it alternates with the origin a fixed point of the cosmic (or Meridian). For other planets also, according to the periodicity of the bricks, their day considered to be.

Also the word day can be part of the day that night not noted. that, in principle, a bright day can be read. Also, the day can be a day of the week or a day from the calendar hint.