חז”ל – “our Sages, of blessed memory,” the abbreviation for חכמנו זכרונם לברכה – Chakhmenu zikhronam li-verakhah, meaning the rabbis of the Mishnah and Talmud, the Tannaim and Amoraim, respectively. Variations are also used, such as רז”ל – Rabbotenu zichronam li-verakhah, “our Rabbis, of blessed memory.”
Belonging to the era of the Tannaim (sing. Tanna – תנא), the rabbis who formulated and transmitted the Oral Law that became the Mishnah in the 1st to 3rd centuries CE. There are seven generations of Tannaim.