(g hard), which means “complement,” is applied to the second part of the Talmud, which consists of annotations, discussions, and amplifications of the Jewish Mishna. There is the Babylonian Gemara and the Jerusalem Gemara. The former, which is the more complete, is by the academies of Babylon; the latter by those of Palestine.
“Scribes and Pharisees ... set little value on the study of the Law
itself, but much on that of the commentaries of the rabbis, now
embodied in the Mishna and Gemara.” —
Source: Dictionary of Phrase and Fable, E. Cobham Brewer, 1894
More on Gemara from Fact Monster: