GMT, or Greenwich Mean Time, is the standard time zone that serves as the reference point for timekeeping worldwide. It is based on the mean solar time at the Prime Meridian, located in Greenwich, England. GMT is often used in aviation, navigation, meteorology, and international telecommunications as a common time standard.
GMT is represented as a 24-hour clock, with times expressed as hours and minutes offset from midnight at the Prime Meridian. For example, 12:00 GMT represents noon at the Prime Meridian, while 18:00 GMT corresponds to 6:00 PM local time in the UK during daylight saving time.
While GMT was historically used as the standard time reference worldwide, it has been largely replaced by Coordinated Universal Time (UTC), which is more precisely defined and maintained using atomic clocks. However, GMT is still commonly used informally and remains an important reference for global timekeeping.