The Mishnah or the Mishna (; Hebrew: מִשְׁנָה, "study by repetition", from the verb shanah שנה, or "to study and review", also "secondary") is the first major written collection of the Jewish oral traditions which is known as the Oral Torah. It is also the first major work of rabbinic literature. The Mishnah was redacted by Judah ha-Nasi at the beginning of the 3rd century CE in a time when, according to the Talmud, the persecution of the Jews and the passage of time raised the possibility that the details of the oral traditions of the Pharisees from the Second Temple period (536 BCE – 70 CE) would be forgotten. Most of the Mishnah is written in Mishnaic Hebrew, but some parts are in Aramaic.
The Mishnah consists of six orders (sedarim, singular seder סדר), each containing 7–12 tractates (masechtot, singular masechet מסכת; lit. "web"), 63 in total, and further subdivided into chapters and paragraphs. The word Mishnah can also indicate a single paragraph of the work, i.e. the smallest unit of structure in the Mishnah. For this reason the whole work is sometimes referred to in the plural form, Mishnayot.