In chronology, a fixed point of time, from which any number of years is begun to be counted; as the Christian Era. It differs from epoch in this; era is a point of time fixed by some nation or denomination of men; epoch is a point fixed by historians and chronologists. The christian era began at the epoch of the birth of Christ.

A succession of years proceeding from a fixed point, or comprehended between two fixed points. The era of the Seleucides ended with the reign of Antiochus.