Princeton's WordNet

1. era, epoch(noun)

   a period marked by distinctive character or reckoned from a fixed point or event

2. epoch, date of reference(noun)

   (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded

3. epoch(noun)

   a unit of geological time that is a subdivision of a period and is itself divided into ages

Wiktionary

1. epoch(Noun)

   A particular period of history, especially one considered remarkable or noteworthy.

2. epoch(Noun)

   A notable event which marks the beginning of such a period.

3. epoch(Noun)

   A precise instant of time that is used as a reference point.

4. epoch(Noun)

   A precise instant of time that is used as a reference point (e.g. January 1, 1970, 00:00:00 UTC).

Webster Dictionary

1. Epoch(noun)

   a fixed point of time, established in history by the occurrence of some grand or remarkable event; a point of time marked by an event of great subsequent influence; as, the epoch of the creation; the birth of Christ was the epoch which gave rise to the Christian era

2. Epoch(noun)

   a period of time, longer or shorter, remarkable for events of great subsequent influence; a memorable period; as, the epoch of maritime discovery, or of the Reformation

3. Epoch(noun)

   a division of time characterized by the prevalence of similar conditions of the earth; commonly a minor division or part of a period

4. Epoch(noun)

   the date at which a planet or comet has a longitude or position

5. Epoch(noun)

   an arbitrary fixed date, for which the elements used in computing the place of a planet, or other heavenly body, at any other date, are given; as, the epoch of Mars; lunar elements for the epoch March 1st, 1860

The New Hacker's Dictionary

1. epoch

   [Unix: prob.: from astronomical timekeeping] The time and date corresponding to 0 in an operating system's clock and timestamp values. Under most Unix versions the epoch is 00:00:00 GMT, January 1, 1970; under VMS, it's 00:00:00 of November 17, 1858 (base date of the U.S. Naval Observatory's ephemerides); on a Macintosh, it's the midnight beginning January 1 1904. System time is measured in seconds or ticks past the epoch. Weird problems may ensue when the clock wraps around (see wrap around), which is not necessarily a rare event; on systems counting 10 ticks per second, a signed 32-bit count of ticks is good only for 6.8 years. The 1-tick-per-second clock of Unix is good only until January 18, 2038, assuming at least some software continues to consider it signed and that word lengths don't increase by then. See also wall time. Microsoft Windows, on the other hand, has an epoch problem every 49.7 days — but this is seldom noticed as Windows is almost incapable of staying up continuously for that long.

• epogAfrikaans
• عَصْرArabic
• епохаBulgarian
• épocaPortuguese (BR)
• epocha, mezníkCzech
• die EpocheGerman
• epokeDanish
• εποχήGreek
• épocaSpanish
• ajajärkEstonian
• آغاز دورانFarsi
• aikakausiFinnish
• époqueFrench
• תְּקוּפָהHebrew
• युगHindi
• epoha, razdobljeCroatian
• kor(szak)Hungarian
• jamanIndonesian
• tímamótIcelandic
• epocaItalian
• 新時代Japanese
• (획기적이고도 특색있는) 시대, 시기Korean
• epochaLithuanian
• laikmetsLatvian
• zamanMalay
• tijdperkDutch
• tid(salder), epokeNorwegian
• epokaPolish
• آغاز دورانPersian
• دوره، عصر، زمانهPashto
• épocaPortuguese
• epocăRomanian
• эпохаRussian
• epocha, medzníkSlovak
• dobaSlovenian
• epohaSerbian
• epokSwedish
• ช่วงเวลาสำคัญในอดีตThai
• çağ, devirTurkish
• 時代，新紀元Chinese (Trad.)
• епоха, добаUkrainian
• کسی عہد کی ابتداUrdu
• kỷ nguyênVietnamese
• 时代，新纪元Chinese (Simp.)