Source : Webster's Revised Unabridged Dictionary (1913)

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.

            The foundation of Solomon's temple is conjectured by
            Ideler to have been an era.           --R. S. Poole.

   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}).

            The first century of our era.         --M. Arnold.

   3. A period of time in which a new order of things prevails;
      a signal stage of history; an epoch.

            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}.

Source : WordNet®

era
     n 1: a period marked by distinctive character or reckoned from a
          fixed point or event [syn: {epoch}]
     2: a major division of geological time; an era is usually
        divided into two or more periods [syn: {geological era}]

Source : Free On-Line Dictionary of Computing

era
     
        Synonym {epoch}.  Webster's Unabridged makes these words
        almost synonymous, but "era" usually connotes a span of time
        rather than a point in time.

ERA
     
        {Entity-Relationship-Attribute}