Tannaim & Amoraim
The great sages of the Mishnah and Talmud.
Reprinted from The Jewish Religion: A Companion, published by Oxford University Press.
The Talmudic Rabbis whose views are recorded in the Talmudic literature are called Tannaim and Amoraim. Both these terms are also found in the Talmud in connection with learning activity. In this context, a Tanna ('rehearser' or 'teacher') was a functionary who rehearsed opinions and statements of the teachers of the first two centuries CE; an Amora ('expounder') was a different functionary, whose job it was to explain to the assembly the words of a contemporary sage, the latter making only a series of brief rulings which the Amora would then explain in detail.
But, in the later passages of the Talmud, both these names were adopted for the two sets of teachers mentioned in the first sense above. The name Tanna was given to the teachers who flourished in Palestine in the first two centuries CE and whose views appear in the Mishnah and other literature from this period. The name Amora was given to the expounders of the Tannaitic teachings.
The Amoraim belong both to Palestine and Babylon down to the end of the fifth century CE. Thus, in the most common usage, the Tannaim are the Palestinian teachers of the first two centuries and the Amoraim the Palestinian and Babylonian teachers from the third to the fifth centuries CE. In the discussions of the Babylonian Talmud, for example, where two different teachers are referred to in the Mishnah, the first is called the Tanna Kama ('the first Tanna').
A Hierarchical System
The general principle followed in the Talmudic arguments is that an Amora is not at liberty to disagree in matters of law with a Tanna unless he can quote another Tanna in support. This principle was no doubt established after the Mishnah had acquired canonical status, so that teachers belonging to the Mishnaic period, whether or not their opinions were actually recorded in the Mishnah, came to enjoy a much greater degree of authority.