en·clave 
(ĕnklāv′, ŏn-)
(ĕnklāv′, ŏn-)n.
1. A country or part of a country lying wholly within the boundaries of another.
2. A distinctly bounded area enclosed within a larger unit: ethnic enclaves in a large city.
[French, from Old French enclaver, to enclose, from Vulgar Latin *inclāvāre : Latin in-, in; see EN-1 + Latin clāvis, key.]