Editing Day (section)

==== Civil day ====
For civil purposes, a common clock time is typically defined for an entire region based on the local mean solar time at a central meridian. Such [[time zone|'' time zones'']] began to be adopted about the middle of the 19th century when [[Rail transport|railroads]] with regularly occurring schedules came into use, with most major countries having adopted them by 1929. As of 2015, throughout the world, 40 such zones are now in use: the central zone, from which all others are defined as offsets, is known as [[UTC+00:00|UTC+00]], which uses [[Coordinated Universal Time|Coordinated Universal Time (UTC)]].

The most common convention starts the civil day at [[midnight]]: this is near the time of the [[Culmination|lower culmination]] of the Sun on the central meridian of the time zone. Such a day may be called a [[calendar day]].

A day is commonly divided into 24 hours, with each hour being made up of 60 minutes, and each minute composed of 60 seconds.