A baraitha is an external piece of Jewish oral law, usually from the same era as the Mishnah and often by the same sages. When Rabbi Judah haNasi compiled the Mishnah, he left out lots of material which could not be included in the 63-volume work for sake of brevity. Some of this found its way into the Tosefta and the Talmud. In the latter it is usually marked by the Aramaic word Tanya, "It was orally taught," or Tanu Rabanan, "Our Rabbis have orally taught," as opposed to Tnan, "We have orally taught" which relates to Mishnah paragraphs.