utc
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Definition
Noun: 1. Coordinated Universal Time: The primary time standard by which the world regulates clocks and time. It is a modern successor to Greenwich Mean Time (GMT), maintained with extreme precision using atomic clocks and adjusted with leap seconds to account for irregularities in Earth's rotation.
Usage
- UTC is used as a global reference for timekeeping in aviation, computing, weather forecasting, and international communication.
- It is typically expressed in a 24-hour format (e.g., 14:30 UTC).
- The term is often used interchangeably with "Zulu time" in military and aviation contexts.
Examples
Advanced Usage
- UTC Offset: The difference in hours and minutes from UTC for a specific time zone (e.g., UTC-5 for Eastern Standard Time, UTC+1 for Central European Time).
- Leap Second: An occasional one-second adjustment added to UTC to keep it aligned with the Earth's slowing rotation. Announcements are made by the International Earth Rotation and Reference Systems Service (IERS).
Variants and Related Words
- GMT (Greenwich Mean Time): Often used synonymously with UTC in casual contexts, though technically GMT is a time zone, while UTC is a time standard.
- Zulu Time (Z): The aviation and military term for UTC.
- TAI (International Atomic Time): The precise atomic time scale from which UTC is derived, but without leap second adjustments.
Synonyms
- World Time
- Universal Time
- Zulu Time
Notes
- UTC is not an acronym but a compromise between the English "Coordinated Universal Time" and the French "Temps Universel Coordonné." It is often erroneously expanded as "Universal Time Coordinated."
- It is the basis for all civil time zones. Local times are defined as UTC plus or minus an offset.
Noun
- Greenwich Mean Time updated with leap seconds