The Collaborative International Dictionary of English v.0.48:

Era \E"ra\, n.; pl. Eras. [LL. aera an era, in earlier usage,
   the items of an account, counters, pl. of aes, aeris, brass,
   money. See Ore.]
   1. A fixed point of time, usually an epoch, from which a
      series of years is reckoned.
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            The foundation of Solomon's temple is conjectured by
            Ideler to have been an era.           --R. S. Poole.
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   2. A period of time reckoned from some particular date or
      epoch; a succession of years dating from some important
      event; as, the era of Alexander; the era of Christ, or the
      Christian era (see under Christian).
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            The first century of our era.         --M. Arnold.
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   3. A period of time in which a new order of things prevails;
      a signal stage of history; an epoch.
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            Painting may truly be said to have opened the new
            era of culture.                       --J. A.
                                                  Symonds.

   Syn: Epoch; time; date; period; age; dispensation. See
        Epoch.
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