A more thorough explanation:

Deportation is when a foreign person is officially sent back to their home country from another country. This usually happens because the person broke the rules of the country they were in. For example, they might have entered the country without permission, stayed too long, or did something illegal. Sometimes, a country might also deport someone who is a danger to others.

In the United States, the deportation process involves the foreign person going before a judge to decide if they should be sent back to their home country. If the judge decides they should be deported, the person will be held in a detention center until their home country agrees to take them back. However, the judge might also decide to let the person stay in the United States instead of being deported.

For example, if someone from Mexico enters the United States without permission and is caught, they might be deported back to Mexico. Or, if someone from Canada is in the United States on a work visa but gets arrested for a serious crime, they might be deported back to Canada.

These examples illustrate how deportation is the formal removal of a foreign person from a country because they broke the rules or are a danger to others.