Definition: A fixed point of time, usually an epoch, from which a series
of years is reckoned.
Definition: 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).
Definition: A period of time in which a new order of things prevails; a
signal stage of history; an epoch.
