AERA is nearly the same thing with epocha, a point of time winch chronologers call a fixed point, or chronological aera. So the first Olympiad, the foundation of Rome, the aera of Nabonassar, of Alexander the Great, of the Seleucidre, (or, in the language of the books of Maccabees, the year of the Greeks,) and the year of Jesus Christ, or Anno Domini, are all aeras.

The AEra of the first Olympiad is fixed A. M. 3228, before Jesus Christ 776.— (2.) The AEra of the foundation of Rome, A. M. 3253, before A. D. 751.— (3.) The .Era of Nabonassar, A. M. 3257, before A. D. 747. — {4.) The JErx of Alexander l?te Great, or his last victory over Darius, A. M. 3674, before A. D. 330.— (5.) The AEra of the Selcucida, A. M. 3692, before A. D. 312. The Jews call this aera the AEra of Contracts, because, when subjected to the government of the Syro-Macedonian kings, they were obliged to insert it in the dates of their contracts and other civil writings. The first book of the Maccabees places the beginning of it in spring, the second places it in autumn. In the Maccabees, it is called " the AEra of the kingdom of the Greeks." All other nations that computed by this rem, began it from the autumn of the year before Christ 312, but the Chaldeans began it from the spring following, because, till then, they did not think Seleucus thoroughly settled in the possession of Babylon. — (6.) The Aera of the birth of Jesus Christ, A. M. 4000, three years at east before our vulgar a?ra, in which we reckon he year 1832 ; whereas, if we take exactly the aera of our Savior's birth, we should reckon it 1836, or at /east 1835. See Epocha, also the Chronological Table. On this subject there are great difficulties to obtain precision ; but we generally add three years to A. D.