[ ep-uhk or, esp. British, ee-pok ]
/ ˈɛp ək or, esp. British, ˈi pɒk /


a particular period of time marked by distinctive features, events, etc.: The treaty ushered in an epoch of peace and good will.
the beginning of a distinctive period in the history of anything: The splitting of the atom marked an epoch in scientific discovery.
a point of time distinguished by a particular event or state of affairs; a memorable date: His coming of age was an epoch in his life.
Geology. any of several divisions of a geologic period during which a geologic series is formed.Compare age(def 12).
  1. an arbitrarily fixed instant of time or date, usually the beginning of a century or half century, used as a reference in giving the elements of a planetary orbit or the like.
  2. the mean longitude of a planet as seen from the sun at such an instant or date.
Physics. the displacement from zero at zero time of a body undergoing simple harmonic motion.

Nearby words

  1. epizootic lymphangitis,
  2. epizootiology,
  3. epizooty,
  4. epns,
  5. epo,
  6. epoch-making,
  7. epochal,
  8. epode,
  9. epoetin alfa,
  10. eponychia

Origin of epoch

1605–15; < New Latin epocha < Greek epochḗ pause, check, fixed time, equivalent to ep- ep- + och- (variant stem of échein to have) + noun suffix

Related formssub·ep·och, nounsu·per·ep·och, noun

Can be confusedepic epoch

Synonym study

1. See age.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019

Examples from the Web for epoch

British Dictionary definitions for epoch


/ (ˈiːpɒk) /


a point in time beginning a new or distinctive periodthe invention of nuclear weapons marked an epoch in the history of warfare
a long period of time marked by some predominant or typical characteristic; era
astronomy a precise date to which information, such as coordinates, relating to a celestial body is referred
geology a unit of geological time within a period during which a series of rocks is formedthe Pleistocene epoch
physics the displacement of an oscillating or vibrating body at zero time
Derived Formsepochal (ˈɛpˌɒkəl), adjectiveepochally, adverb

Word Origin for epoch

C17: from New Latin epocha, from Greek epokhē cessation; related to ekhein to hold, have

Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

Word Origin and History for 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 Late Latin epocha, from Greek epokhe "stoppage, fixed point of time," from epekhein "to pause, take up a position," from epi "on" (see epi-) + ekhein "to hold" (see scheme (n.)). Transferred sense of "a period of time" is 1620s; geological usage (not a precise measurement) is from 1802.

Online Etymology Dictionary, © 2010 Douglas Harper

Science definitions for epoch


[ ĕpək, ēpŏk′ ]

The shortest division of geologic time. An epoch is a subdivision of a period.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.