The Collaborative International Dictionary of English v.0.48:

Deportation \De`por*ta"tion\, n. [L. depotatio: cf. F.
   d['e]portation.]
   The act of deporting or exiling, or the state of being
   deported; banishment; transportation.
   [1913 Webster]

         In their deportations, they had often the favor of
         their conquerors.                        --Atterbury.
   [1913 Webster]

WordNet (r) 3.0 (2006):

deportation
    n 1: the act of expelling a person from their native land; "men
         in exile dream of hope"; "his deportation to a penal
         colony"; "the expatriation of wealthy farmers"; "the
         sentence was one of transportation for life" [syn: exile,
         deportation, expatriation, transportation]
    2: the expulsion from a country of an undesirable alien

Bouvier's Law Dictionary, Revised 6th Ed (1856):

DEPORTATION, 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.