When Great Grandpa was leaving a country permanently to settle in another, he was an EMIGRANT. While in the process of leaving, he was EMIGRATING. When he arrived at the new location where he intended to settle, he was an IMMIGRANT and when we speak of his coming to a new place, he was IMMIGRATING. Should his journey have been because of war, political unrest or other oppressions, his leaving one country for another made him an EMIGRE. If there was a bit of gypsy in his soul and he moves from place to place without settling, he was MIGRATING. Got it?