What is the difference in immigration, emigration and to migrate?

peasypod

Migrate, which is used of people and animals, sometimes implies a lack of permanent settlement, especially as a result of seasonal or periodic movement. Emigrate and immigrate are used only of people and imply a permanent move, generally across a political boundary. Emigrate describes the move relative to the point of departure: After the Nazis came to power in Germany, many scientists emigrated (that is, left Germany). By contrast, immigrate describes the move relative to the destination: The promise of prosperity in the United States encouraged many people to immigrate (that is, move to the United States). Source: Dictionary.com Feb 10 05, 6:17 PM