Immigration is the act of entering a new country. Immigrants are the people who do the entering. Since more people enter the US than leave it, our national conversation is typically about immigration. For example, Americans may debate the costs and benefits of Mexican immigration (i.e., the inflow of people from Mexico).
Emigration is the other side of immigration: it’s the act of leaving one’s country of birth. Emigrants are what we call the people who do the leaving. Since more people tend to leave Mexico than enter it, Mexico’s national conversation is more often about emigration. For example, Mexicans may debate the costs and benefits of mass emigration to the United States (i.e., the outflow of people to the United States).
Think: i for in, e for exit.
Then there’s the term net migration. This refers to the number of immigrants who have entered a country minus the number of emigrants who have left. If a country is said to have positive net migration, that means more people enter than leave. If a country has negative net migration, that means more people leave than enter.