concentration camps are places in the world where people are being held prisoners and being torchered/raped/killed. for example, Adolf Hitler and the nazis. they held tons of those camps for the jews to be torchered to death because of racisim. go to history class.
summary:
Extermination camps: camps where jews were ultimately killed. more than three million people were killed at extermination camps.
Transit camps: camps where jewish prisoners were held to be exported to other camps
Forced labour camps: what it sounds like. the nazi held these camps for jews to do labour.
Prisoner of war camps: again, what it sounds like. officers, comanders, pilots, all jewish war people were captured and put here.