"to pass into a place as a new inhabitant or resident," especially "to move to a country where one is not a native, for the purpose of settling permanently there," 1620s, from Latin immigratus, past participle of immigrare "to remove, go into, move in," from assimilated form of in- "into, in, on, upon" (from PIE root *en "in") + migrare "to move" (see migration). Related: Immigrated; immigrating.