What is Exile?

Legal Definition
To be in exile means to be away from one's home (i.e. city, state, or country), while either being explicitly refused permission to return and/or being threatened with imprisonment or death upon return. It can be a form of punishment and solitude. It is common to distinguish between "internal exile", i.e., forced resettlement within the country of residence, and "external exile", which is deportation outside the country of residence. Although most commonly used to describe an individual situation, the term is also used for groups (especially ethnic or national groups), or for an entire government. Terms such as "diaspora" and "refugee" describe group exile, both voluntary and forced, and "government in exile" describes a government of a country that has been forced to relocate and argue its legitimacy from outside that country. Exile can also be a self-imposed departure from one's homeland. Self-exile is often depicted as a form of protest by the person who claims it, to avoid persecution or legal matters (such as tax or criminal allegations), an act of shame or repentance, or isolating oneself to be able to devote time to a particular pursuit. Article 9 of the Universal Declaration of Human Rights states that "No one shall be subjected to arbitrary arrest, detention or exile."
-- Wikipedia
Legal Definition
Civil law. The: interdiction of all places except one in which the party is foreed to make his residence.

2. This punishment did not deprive the sufferer of his right of citizenship or of his property, unless the exile were perpetual, in which case confiscation not unfrequently was a part of the sentence. Exile was temporary or perpetual. Dig. 48, 22, 4; Code, 10, 59, 2. Exile differs from deportation, (q. v.) and relegation. (q. v.) Vide, 2 Lev. 191; Co. Litt. 133, a.
-- Bouviers Law Dictionary
Legal Definition
Banishment; the person banished.
-- Black's Law Dictionary
Legal Definition
To banish; one banished.
-- Ballentine's Law Dictionary