The Jewish Oral law was recorded by Rabbi Judah the Prince and redacted as the Mishna in 200 CE. The oral traditions were committed to writing to preserve them, as it became apparent that the Palestine Jewish community, and its learning, was threatened. The rabbis of the Mishnah are known as Tannaim; many teachings in the Mishnah are reported in the name of a specific Tanna.
Over the next three centuries the Mishna underwent analysis and debate in Israel and Babylon (the world's major Jewish communities). This analysis is known as Gemara. The rabbis of the Gemara are referred to as Amoraim. The analysis of the Amoraim is generally focused on clarifying the positions, words and views of the Tannaim.
The Mishnah and the Gemara together comprise the Talmud. The Talmud is thus the combination of a core text, the Mishnah, or “redaction” (from the verb shanah to repeat, revise) and subsequent analysis and commentary, the gemara, or “completion” (from gamar).