migration: to go from one country to another with intentions of settling.
emigration: the demonstration of leaving ones own nation to settle forever in another/moving to another country.
immigration: the action of coming to live permanently in a foreign country.
circulation: (im not really sure of this answer) but i think it means free development or moving about in a particular course.
push factors: something that makes someone want to leave a place.
-hope this helped! <3