\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.