enclave

A political, cultural or social entity or part thereof that is completely surrounded by another.

The Republic of San Marino is an enclave of Italy.

The streets around Union Square form a Protestant enclave within an otherwise Catholic neighbourhood.

A group that is set off from a larger population by its characteristic or behavior.

They were learning to do what in all my years in the music business I never saw — which was women running a record company, women producing concerts, women learning to be engineers, women moving into this absolutely all-male enclave. You never saw a woman in any of those positions, in any of that work except as secretaries and "go-fers".

What is unbearable, in fact, is the feeling, 13 years after 9/11, that America has been chasing its tail; that, in some whack-a-mole horror show, the quashing of a jihadi enclave here only spurs the sprouting of another there; that the ideology of Al Qaeda is still reverberating through a blocked Arab world whose Sunni-Shia balance (insofar as that went) was upended by the American invasion of Iraq.

An isolated portion of an application's address space, such that data in an enclave can only be accessed by code in the same enclave.

When an enclave spans a system boundary in a sysplex, it is called a multisystem enclave.

To enclose within a foreign territory.