ERA

noun a fixed point of time, usually an epoch, from which a series of years is reckoned.

2. era ·noun a period of time in which a new order of things prevails; a signal stage of history; an epoch.

3. era ·noun 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).