Epoch (timekeeping)
- Note: This article grew out of the Epoch disambiguation page.
- For epoch in the sense of an extended period of geologic time, see geologic timescale.
An epoch is the moment in time at which a timekeeping system begins to be counted. For example, the epoch of the international calendar system is the year 1 AD, while the epoch of the Islamic calendar occurred in 622 AD, and is called AH 1 in Muslim cultures.
Calendar systemsThe epoch of a calendar era is the year, day, or instant from which the later (and earlier) years of a calendar are counted.
AstronomyIn astronomy, an epoch is a moment in time for which celestial coordinates or orbital elements are specified. The current standard epoch is J2000.0.
Technology
ComputingIn computing, an epoch is a specific date and time used as the reference for all other times. The Unix epoch is an example.
TelecommunicationsIn telecommunication, an epoch date is a date in history, chosen as the reference date from which time is measured.
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