Mishnah Gittin 4:3

When the term tikkun olam — translated as “repair,” “betterment,” or “improvement” of the world — first appears throughout the fourth chapter of tractate Gittin in the Mishnah, it refers to rabbinic edicts likely meant to foster social order, like Hillel’s prozbul and the decree that two witnesses must sign a divorce document. In the ancient Aleinu prayer, the term is used in the context of a future messianic era in which idolatry would be obliterated, and all would recognize God’s omnipotence. In kabbalistic literature, tikkun olam means performing religious acts in order to gather fragments of God’s light and return them to their source. In modern times, many use "tikkun olam" to refer to pursuing social justice.

Shemittah, or the sabbatical year, is the seventh year of the seven-year agricultural cycle mandated by the Torah in the land of Israel. During the Shemittah year, working the land is prohibited, produce that grows on the land takes on sacred status, and debts are forgiven. Shemittah is first mentioned in the Torah in Exodus 23:10-11.

Tikkun means “repair” or “mend.” It is used alongside the word olam (world) to express the Jewish responsibility to repair the world. Tikkun can also refer to specific texts read on various occasions, specific nights of Torah study, such as Hoshanah Rabbah and Shavuot, the process of making a shared courtyard into a personal space so that one can carry in it on Shabbat, or the process of improving character traits.