What is Deportation?

Legal Definition
Civil law. Among the Romans a perpetual banishment, depriving the banished of his rights as a citizen; it differed from relegation (q. v.) and exile. (q. v.). 1 Bro. Civ. Law, 125 note; Inst. 1, 12, 1 and 2; -Dig. 48, 22, 14, 1.
-- Bouviers Law Dictionary
Legal Definition
Banishment to a foreign country, attended with confiscation of property and deprivation of civil rights. A punishment derived from the deportatio (q. v.) of the Roman law, and still in use in France.

In Roman law. A perpetual banishment, depriving the banished of his rights as a citizen; it differed from relegation (q. v.) and exile, (q. v.) 1 Brown, Civil & Adm. Law, 125, note; Inst 1, 12, 1, and 2; Dig. 48, 22, 14, 1.

In American law. The removal or sending back of an alien to the country from which he came, as a measure of national police and without any implication of punishment or penalty. "Transportation," "extradition," and "deportation," although each has the effect of removing a person from a country, are different things and for different purposes. Transportation is by way of punishment of one convicted of an offence against the laws of the country; extradition is the surrender to another country of one accused of an offence against its laws, there to be tried and punished if found guilty.

Deportation is the removing of an alien out of the country simply because his presence is deemed inconsistent with the public welfare, and without any punishment being imposed or contemplated, either under the laws of the country out of which he is sent, or under those of the country to which he is taken. Fong Yue Ting v. U. S.. 149 U. S. 698, 13 Sup. Ct 1016, 37 In Ed. 905.
-- Black's Law Dictionary
Legal Definition
Deportation is the expulsion of a person or group of people from a place or country.
-- Wikipedia
Legal Definition
The official removal of an alien from a country.
Legal Definition
Removal of an alien from the country. See 149 U. S. 709, 37 L. Ed. 912, 13 Sup. Ct. Rep. 1016.
-- Ballentine's Law Dictionary