'Immigration' definitions:

Definition of 'immigration'

From: WordNet
noun
Migration into a place (especially migration to a country of which you are not a native in order to settle there) [syn: immigration, in-migration]
noun
The body of immigrants arriving during a specified interval; "the increased immigration strengthened the colony"

Definition of 'Immigration'

From: GCIDE
  • Immigration \Im"mi*gra"tion\, n. [Cf. F. immigration.] The act of immigrating; the passing or coming into a country for the purpose of permanent residence. [1913 Webster]
  • The immigrations of the Arabians into Europe. --T. Warton. [1913 Webster]