D defs.my
Entry 3 senses Webster, 1913

Era

/ĕrʹə/ · E·ra · IPA /ˈɪə.ɹə/
01 n. A fixed point of time, usually an epoch, from which a series of years is reckoned.
pl. Eras ((#))
  1. 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. 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). See: Christian
    “The first century of our era.” M. Arnold.
  3. 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.