Pale of Settlement
The Pale of Settlement (with "pale" being an archaic term derived from the Latin palus meaning stake, extended to mean the area enclosed by a fence or boundary) was a western region of Imperial Russia, with varying borders, which existed from 1791 to 1917. It included relatively newly acquired territories in which many Jews lived.
In this region, permanent residency by Jews was allowed, but beyond it, Jewish residency, permanent or temporary, was mostly forbidden. Most Jews were still excluded from residency in a number of cities within the Pale as well. A limited number of Jews were allowed to live outside the area, including those with university education, the ennobled, members of the most affluent of the merchant guilds and particular artisans, some military personnel and some services associated with them, including their families, and sometimes the servants of these.
Conversion to Russian Orthodoxy, the state religion, released individuals from the restrictions.