Epoch

5 definitions found

From The Collaborative International Dictionary of English v.0.48 [gcide]:

  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. 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.
        [1913 Webster]
  
              In divers ages, . . . divers epochs of time were
              used.                                 --Usher.
        [1913 Webster]
  
              Great epochs and crises in the kingdom of God.
                                                    --Trench.
        [1913 Webster]
  
              The acquittal of the bishops was not the only event
              which makes the 30th of June, 1688, a great epoch in
              history.                              --Macaulay.
        [1913 Webster]
  
     Note: Epochs mark the beginning of new historical periods,
           and dates are often numbered from them.
           [1913 Webster]
  
     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.
        [1913 Webster]
  
              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.
        [1913 Webster]
  
     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.
        [1913 Webster]
  
              The long geological epoch which stored up the vast
              coal measures.                        --J. C.
                                                    Shairp.
        [1913 Webster]
  
     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.
            [1913 Webster]
  
                  The capture of Constantinople is an epoch in the
                  history of Mahometanism; but the flight of
                  Mahomet is its era.               --C. J. Smith.
            [1913 Webster]

From WordNet (r) 2.0 [wn]:

  epoch
       n 1: a period marked by distinctive character or reckoned from a
            fixed point or event [syn: {era}]
       2: (astronomy) the precise date that is the point of reference
          for which information (as coordinates of a celestial body)
          is referred [syn: {date of reference}]
       3: a unit of geological time

From Moby Thesaurus II by Grady Ward, 1.0 [moby-thes]:

  20 Moby Thesaurus words for "epoch":
     Bronze Age, Dark Ages, Depression Era, Golden Age, Ice Age,
     Iron Age, Jacksonian Age, Middle Ages, New Deal Era,
     Prohibition Era, Silver Age, Steel Age, Stone Age, age, days, era,
     glacial epoch, interval, term, time
  
  

From Jargon File (4.3.1, 29 Jun 2001) [jargon]:

  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 {tick}s
     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.
  
  

From The Free On-line Dictionary of Computing (27 SEP 03) [foldoc]:

  epoch
       
          1. [Unix: probably 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 US Naval Observatory's
          ephemerides); on a Macintosh, it's the midnight beginning
          January 1 1904.  System time is measured in seconds or {tick}s
          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}.
       
          2. (Epoch) A version of {GNU Emacs} for the {X Window System}
          from {NCSA}.
       
          [{Jargon File}]