An exclave, on the other hand, is a territory legally or politically attached to another territory with which it is not physically contiguous.
These are two distinct concepts, although many entities fit both definitions. In Fig. 1 at right, C is an exclave of B, and is also an enclave within A. If C were independent it would be an enclave but not an exclave. In Fig. 2 at right, C is again an exclave of B, but is not an enclave, because it has boundaries with more than one entity.
The word enclave entered the English jargon of diplomacy in 1868. It derives from French, which was then the lingua franca of diplomacy, with a sense inherited from Late Latin inclavatus meaning shut in, locked up (with a key, Latin clavis). The word exclave is a logical extension created three decades later.
Although the meanings of both words are close, an exclave may not necessarily be an enclave or vice versa. For example, Kaliningrad, an exclave of Russia, is not an enclave because it is surrounded not by one state, but by two: Lithuania and Poland; it also borders the Baltic Sea. Conversely, Lesotho is an enclave in South Africa, but it is not politically attached to anything else, meaning that it is not an exclave.
In British administrative history, subnational enclaves were usually called detachments or detached parts. In English ecclesiastic history, subnational enclaves were known as peculiars (see also Royal Peculiar).
A country surrounded by another but having access to the sea is not considered to be an enclave, regardless of size. For this reason Portugal is not an enclave of Spain, and Gambia is not an enclave of Senegal.
In medicine, an exclave is a detached part of an organ, as of the pancreas, thyroid, or other gland.
Since living in an enclave can be very inconvenient and many agreements have to be found by both countries over mail addresses, power supply or passage rights, enclaves tend to be eliminated and many cases that existed before have now been removed.
Many exclaves today have an independence movement, especially if the exclave is far away from the mainland.