Internment is the state being confined. It is similar to prison but people are put in internment usually for political reasons. Examples can be the concentration camp for the Jews during World War II or the Internment of Japanese Americans, which was also used during World War II.
Internment means being imprisoned or jailed as a prisoner. This is usually for military reasons or political reasons during war. Internment is usually focused on a certain group, race, or religious group of people