Hitler was appointed Chancellor on 30 January 1933. Immediately, the SA stepped up their campaign of violence and terror against their political opponents on the left.
Across Germany the local police and SA and SS rounded up many thousands of communists, socialists, church leaders and anyone else who might criticise the Nazis.
As prisoners were physically concentrated in one place the Nazis called these first camps concentration camps.
Over the next twelve years, as they invaded and occupied lands all over Europe, the Nazis would build over 40,000 camps of various kinds. These included concentration camps, transit camps, forced labour or work camps and death camps.