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From Medieval Latin epocha, from Ancient Greek ἐποχή (epokhḗ, a check, cessation, stop, pause, epoch of a star, i.e., the point at which it seems to halt after reaching the highest, and generally the place of a star; hence, a historical epoch), from ἐπέχω (epékhō, I hold in, check), from ἐπι- (epi-, upon) + ἔχω (ékhō, I have, hold).


  • (UK) IPA(key): /ˈiːˌpɒk/, /ˈɛpˌək/
  • (US) IPA(key): /ˈɛpˌək/, /ˈɛpˌɑk/, /ˈipˌɑk/, /ˈeɪˌpɑk/
  • (file)


epoch (plural epochs)

  1. A particular period of history, especially one considered noteworthy or remarkable.
    • 2012 January, Donald Worster, “A Drier and Hotter Future”, in American Scientist[1], volume 100, number 1, page 70:
      Phoenix and Lubbock are both caught in severe drought, and it is going to get much worse. We may see many such [dust] storms in the decades ahead, along with species extinctions, radical disturbance of ecosystems, and intensified social conflict over land and water. Welcome to the Anthropocene, the epoch when humans have become a major geological and climatic force.
  2. A notable event which marks the beginning of such a period.
  3. (astronomy) A precise instant of time that is used as a point of reference.
  4. (computing) Uses in computing.
    1. A precise instant of time that is used as a point of reference (e.g., January 1, 1970, 00:00:00 UTC).
    2. One complete presentation of the training data set to an iterative machine learning algorithm.
      The neural network was trained over 500 epochs.
  5. (geology) A unit of geologic time subdividing a period into smaller parts.


  • (particular period in history): age, era (only in general usage; in geology the words age, epoch, and era have specific meanings)

Related terms[edit]


The translations below need to be checked and inserted above into the appropriate translation tables, removing any numbers. Numbers do not necessarily match those in definitions. See instructions at Wiktionary:Entry layout#Translations.


epoch (third-person singular simple present epochs, present participle epoching, simple past and past participle epoched)

  1. (sciences, transitive) To divide (data) into segments by time period.
    • 2015 July 6, “Stronger Neural Modulation by Visual Motion Intensity in Autism Spectrum Disorders”, in PLOS ONE[2], DOI:10.1371/journal.pone.0132531:
      The continuous data were epoched into segments of 1500 ms (starting 500 ms before visual stimulus onset), time-locked to stimulus onset (0 ms) and sorted according to experimental conditions.

Further reading[edit]