epoch


epoch
   1. a measure of time used in astronomy. In an epoch system, times are specified as years and fractions of years (such as epoch 1998.5). To set a starting point for the system, a specific epoch time must be fixed as a particular clock time of a particular date. In 1984, the International Astronomical Union agreed that epoch times should be fixed by requiring that epoch 2000.0 equals 12 hours Universal Time of the day 2000 January 1. Other epoch conventions were used in the past. See also Julian epoch. The name comes from a Greek word epoche meaning a stopping point or fixed point.
   2. a unit of time equal to 19 years, used in predictions of the tides. In this use, an epoch is another name for a Metonic cycle. All possible alignments of the sun and moon occur in this 19-year cycle, so tidal heights and other tidal phenomena are averaged over this period.

Dictionary of units of measurement. 2015.

Synonyms:
, , , , (remarkable for some event)


Look at other dictionaries:

  • Epoch — Ep och ([e^]p [o^]k or [=e] p[o^]k; 277), n. [LL. epocha, Gr. epochh check, stop, an epoch of a star, an historical epoch, fr. epe chein to hold on, check; epi upon + e chein to have, hold; akin to Skr. sah to overpower, Goth. sigis victory, AS.… …   The Collaborative International Dictionary of English

  • epoch — 1. An epoch is the beginning of a distinctive period in the history of something or someone, whereas an era is a period of history characterized by particular circumstances or by a particular series of events. A period is a more general term for… …   Modern English usage

  • Epoch Co. — Epoch Co., Ltd. is a Japanese toy and computer games company founded in 1958 which is best known for manufacturing Barcode Battler and Doraemon video games. Its current Representative President is Road Yutaka MaedaHistoryFounded in May 1958 by… …   Wikipedia

  • Epoch — (dt. Epoche) bezeichnet im deutschen Sprachgebrauch die Epoche der Unixzeit zwei US amerikanische Science Fiction Filme, siehe Torus – Das Geheimnis aus einer anderen Welt (Epoch), Epoch: Evolution (2003) einen japanischen Hersteller von… …   Deutsch Wikipedia

  • Epoch — Epoch  неоднозначный термин. Возможные значения: Epoch  японская компания по производству детских игрушек. Unix Epoch  UNIX время, система описания моментов во времени, принятая в UNIX …   Википедия

  • epoch — [ep′ək; ] also [ ep′äk΄; ] Cdn & Brit usually [ ē′päk΄] n. [ML epocha < Gr epochē, a check, cessation < epechein, to hold in, check < epi , upon + echein, to hold: see SCHEME] 1. the beginning of a new and important period in the history …   English World dictionary

  • epoch — index age, cycle, duration, lifetime, period, phase (period) Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • epoch — 1610s, epocha, point marking the start of a new period in time (e.g. the founding of Rome, the birth of Christ, the Hegira), from L.L. epocha, from Gk. epokhe stoppage, fixed point of time, from epekhein to pause, take up a position, from epi on… …   Etymology dictionary

  • epoch — era, age, *period, aeon …   New Dictionary of Synonyms

  • epoch — [n] period age, date, era, span, time; concepts 807,822 …   New thesaurus

  • epoch — ► NOUN 1) a period of time marked by particular events or characteristics. 2) the beginning of a period of history. 3) Geology a division of time that is a subdivision of a period and is itself subdivided into ages. DERIVATIVES epochal adjective …   English terms dictionary


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