The SS (Schutzstaffel) was a paramilitary organization within the Nazi Party responsible for implementing Hitler's ideology of racial purity and political control. Some synonyms for the SS include the Nazi Gestapo, the Third Reich's secret police, and the Waffen-SS, the armed wing of the SS. The Einsatzgruppen was a mobile killing unit subordinate to the SS, responsible for exterminating Jews and other "undesirable" persons. The term SS is often used to refer to the entire organization, but it is important to note the different subgroups and their specific roles in carrying out Hitler's genocidal agenda during the Holocaust.