from The American Heritage® Dictionary of the English Language, 5th Edition.

  • noun A particular period of history, especially one considered remarkable or noteworthy.
  • noun A unit of geologic time that is a division of a period.
  • noun Astronomy An instant in time that is arbitrarily selected as a point of reference for specification of celestial coordinates.

from The Century Dictionary.

  • noun In the mechanics of vibration, a term introduced into the equation for a simple harmonic motion in cases where time is not reckoned from the instant when the vibrating particle has reached its greatest positive elongation.
  • noun A point of time from which succeeding years are numbered; especially, a point of time distinguished by some remarkable event, or the event itself as distinguishing the time of its occurrence.
  • noun Hence A specific period of time; any space of time considered as a unit with reference to some particular characteristic or course of events.
  • noun In geology, specifically, one of the shorter divisions of geological time.
  • noun In astronomy, an arbitrary fixed date, for which the elements of a planetary or cometary orbit, or of any motion, are given.
  • noun See the adjectives.
  • noun See equivalent phrases under era.
  • noun Synonyms Epoch, Era, Period, Age. Epoch and era should be distinguished, though in common usage they are interchanged. “An era is a succession of time: an epoch is a point of time. An era commonly begins at an epoch. We live in the Christian era, in the Protestant era, in the era of liberty and letters. The date of the birth of Christ was an epoch: the period of the dawn of the Reformation was an epoch” (A. Phelps, Eng. Style, p. 365). Period may be the opposite of epoch, in being the date at which anything ends, or it may be mere duration, or duration from point to point; the word is very free and often indefinite in its range of meaning. The meaning of age is modified by its connection with human life, so as often to be associated with a person: as, the age of Pericles; but it is also freely applied to time, viewed as a period of some length: as, the bronze age; the golden age; this is an age of investigation.

from the GNU version of the Collaborative International Dictionary of English.

  • 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
  • noun A period of time, longer or shorter, remarkable for events of great subsequent influence; a memorable period.
  • noun (Geol.) A division of time characterized by the prevalence of similar conditions of the earth; commonly a minor division or part of a period.
  • noun The date at which a planet or comet has a longitude or position.
  • 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

from Wiktionary, Creative Commons Attribution/Share-Alike License.

  • noun A particular period of history, especially one considered remarkable or noteworthy.
  • noun A notable event which marks the beginning of such a period.
  • noun astronomy A precise instant of time that is used as a reference point.
  • noun computing, uncountable A precise instant of time that is used as a reference point (e.g. January 1, 1970, 00:00:00 UTC).

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • noun (astronomy) an arbitrarily fixed date that is the point in time relative to which information (as coordinates of a celestial body) is recorded
  • noun a unit of geological time that is a subdivision of a period and is itself divided into ages
  • noun a period marked by distinctive character or reckoned from a fixed point or event


from The American Heritage® Dictionary of the English Language, 4th Edition

[Medieval Latin epocha, measure of time, from Greek epokhē, a point in time; see segh- in Indo-European roots.]

from Wiktionary, Creative Commons Attribution/Share-Alike License

From Medieval Latin epocha, from Ancient Greek ἐποχή (epokhē, "a check, cessation, stop, pause, epoch of a star, e.g., the point at which it seems to halt after reaching the highest, and generally the place of a star; hence, a historical epoch"), from ἐπέχειν (epechein, "to hold in, check"), from ἐπί (épí, "upon") + ἔχειν (echein, "to have, hold").


  • Special elections require time, and, especially in epoch of such delicacy, special elections may inhibit the ability to pass important legislation.

    Matthew Yglesias » Against Appointed Senators

  • Marriage, whatever its particular manifestation in a particular culture or epoch, is essentially about who may and who may not have sexual access to a woman when she becomes an adult, and is also about how her adulthood -- and sexual accessibility -- is defined.

    When You're Desperate

  • In this street, stunt performers in epoch dresses walked around Lisbon in old cars and distributed the "Mad Men News" newspaper.

    Mad Men

  • In this street, stunt performers in epoch dresses walked around Lisbon in old cars and distributed the "Mad Men News" newspaper.

    Archive 2008-10-01

  • The correlation of all these factors and which ones may be dominant during a given epoch is still the subject of intense research and is more of a guesstimate than firmly established scientific fact†¦ ..

    Think Progress » Big Oil Launches Attack On Al Gore

  • Because many computers today store the number of seconds as a 32-bit signed integer, the Unix epoch is often said to last 231 seconds, thus “ending” at 03: 14: 07 Tuesday, January 19, 2038 (UTC).

    2004 August

  • This is a fact the significance of which cannot escape anyone, and one which incontestably marks an epoch from the point of view of chemists.

    Marie Curie - Nobel Lecture

  • The slowness of historical change, the fact that any epoch always contains a great deal of the last epoch, is never sufficiently allowed for.

    James Burnham and the Managerial Revolution

  • A French writer said a year or two, ago, 'our epoch is not particularly gay but it is passionately interesting.

    Masters of Our Fate

  • As the Davidic epoch is the point of the covenant-people's highest glory, so the captivity is that of their lowest humiliation.

    Commentary Critical and Explanatory on the Whole Bible


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  • "No, it is impossible; it is impossible to convey the life-sensation of any given epoch of one's existence--that which makes its truth, its meaning--its subtle and penetrating essence." --Heart of Darkness, Joseph Conrad

    March 9, 2011