Techum shabbat
In Jewish halacha, the techum shabbat (Hebrew: תחום שבת, "Shabbat limit"), or simply techum, is a limited physical area in which a Jew is permitted to travel on Shabbat and Jewish holidays. In general, this area is calculated by measuring 2000 cubits (about 1 kilometer) in every direction from the place (or settlement) where a person was located when Shabbat began.