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epoch - 8 dictionary results

ep⋅och

[ep-uh

k or, especially Brit., ee-pok]

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–noun

1.	a particular period of time marked by distinctive features, events, etc.: The treaty ushered in an epoch of peace and good will.

2.	the beginning of a distinctive period in the history of anything: The splitting of the atom marked an epoch in scientific discovery.

3.	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.

4.	Geology. any of several divisions of a geologic period during which a geologic series is formed. Compare age (def. 12).

Astronomy.

a.	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.

b.	the mean longitude of a planet as seen from the sun at such an instant or date.

6.	Physics. the displacement from zero at zero time of a body undergoing simple harmonic motion.

Origin:
1605–15; < NL epocha < Gk epoch

pause, check, fixed time, equiv. to ep- ep- + och- (var. s. of échein to have) + -ē n. suffix

Synonyms:
1. age, date, era, time. See age.

Dictionary.com Unabridged
Based on the Random House Dictionary, © Random House, Inc. 2009.
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Link To epoch

ep·och (ěp'ək, ē'pŏk')

1. A particular period of history, especially one considered remarkable or noteworthy.
2. A notable event that marks the beginning of such a period. See Synonyms at period.
A unit of geologic time that is a division of a period.
Astronomy An instant in time that is arbitrarily selected as a point of reference.

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

The American Heritage® Dictionary of the English Language, Fourth Edition
Copyright © 2009 by Houghton Mifflin Company.
Published by Houghton Mifflin Company. All rights reserved.
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Epoch

Ep"och\ (?; 277), n. [LL. epocha, Gr. ? check, stop, an epoch of a star, an historical epoch, fr. ? to hold on, check; 'epi` upon + ? to have, hold; akin to Skr. sah to overpower, Goth. sigis victory, AS. sigor, sige, G. sieg: cf. F. ['e]poque. See Scheme.]

1. 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.

In divers ages, . . . divers epochs of time were used. --Usher.

Great epochs and crises in the kingdom of God. --Trench.

The acquittal of the bishops was not the only event which makes the 30th of June, 1688, a great epoch in history. --Macaulay.

Note: Epochs mark the beginning of new historical periods, and dates are often numbered from them.

2. 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. "So vast an epoch of time." --F. Harrison.

The influence of Chaucer continued to live even during the dreary interval which separates from one another two important epochs of our literary history. --A. W. Ward.

3. (Geol.) A division of time characterized by the prevalence of similar conditions of the earth; commonly a minor division or part of a period.

The long geological epoch which stored up the vast coal measures. --J. C. Shairp.

4. (Astron.) (a) The date at which a planet or comet has a longitude or position. (b) 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.

Syn: Era; time; date; period; age.

Usage: Epoch, Era. We speak of the era of the Reformation, when we think of it as a period, during which a new order of things prevailed; so also, the era of good feeling, etc. Had we been thinking of the time as marked by certain great events, or as a period in which great results were effected, we should have called the times when these events happened epochs, and the whole period an epoch.

The capture of Constantinople is an epoch in the history of Mahometanism; but the flight of Mahomet is its era. --C. J. Smith.

Language Translation for : epoch

Spanish: época,

German: die Epoche,

Japanese: 新時代

More Translations »

epoch

n. [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.

era

n. Syn. {epoch}. Webster's Unabridged makes these words almost synonymous, but `era' more often connotes a span of time rather than a point in time, whereas the reverse is true for {epoch}. The {epoch} usage is recommended.

Jargon File 4.2.0
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epoch

1614, "point marking the start of a new period in time" (e.g. the founding of Rome, the birth of Christ, the Hegira), from M.L. epocha, from Gk. epokhe "stoppage, fixed point of time," from epekhein "to pause, take up a position," from epi- "on" + ekhein "to hold." Transf. sense of "a period of time" is c.1628; geological usage (not a precise measurement) is from 1802.

epoch (ěp'ək, ē'pŏk') Pronunciation Key
The shortest division of geologic time. An epoch is a subdivision of a period.

epoch
1. (Probably from astronomical timekeeping) A term used originally in Unix documentation for the time and date corresponding to zero in an operating system's clock and timestamp values.
Under most Unix versions the epoch is 1970-01-01 00:00:00 GMT; under VMS, it's 1858-11-17 00:00:00 (the base date of the US Naval Observatory's ephemerides); on a Macintosh, it's 1904-01-01 00:00:00.
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 0.1 * 2**31-1 seconds, or 6.8 years. The one-tick-per-second clock of Unix is good only until 2038-01-18, assuming at least some software continues to consider it signed and that word lengths don't increase by then. See also wall time.
2. (Epoch) A version of GNU Emacs for the X Window System from NCSA.
[The Jargon File]
(2004-06-10)

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