Germany implemented the persecution in stages. Following Adolf Hitler's rise to power in 1933, the government passed laws to exclude Jews from civil society, most prominently the Nuremberg Laws in 1935. Starting in 1933, the Nazis built a network of concentration camps in Germany for political opponents and people deemed "undesirable". After the invasion of Poland in 1939, the regime set up ghettos to segregate Jews. Over 42,000 camps, ghettos, and other detention sites were established.
The deportation of Jews to the ghettos culminated in the policy of extermination the Nazis called the "Final Solution to the Jewish Question", discussed by senior Nazi officials at the Wannsee Conference in Berlin in January 1942. As German forces captured territories in the East, all anti-Jewish measures were radicalized. Under the coordination of the SS, with directions from the highest leadership of the Nazi Party, killings were committed within Germany itself, throughout German-occupied Europe, and across all territories controlled by the Axis powers. Paramilitary units called Einsatzgruppen murdered around 1.3 million Jews in mass shootings between 1941 and 1945. By mid-1942, victims were being deported from the ghettos in sealed freight trains to extermination camps where, if they survived the journey, they were killed in gas chambers. The killing continued until the end of World War II in Europe in April–May 1945.
The term holocaust comes from the Greek ὁλόκαυστος holókaustos: hólos, "whole" and kaustós, "burnt offering", "a sacrifice or offering entirely consumed by fire". Later it came to denote large-scale destruction or slaughter. The biblical term shoah (שואה; also transliterated sho'ah and shoa), meaning "destruction", became the standard Hebrew term, first used in a pamphlet in 1940, for the murder of the European Jews. The term Holocaust was used by historians in the 1950s as a translation of Shoah, and in 1968 the Library of Congress created a new category, "Holocaust, Jewish (1939–1945)". The NBC television mini-series Holocaust (1978) is credited with having helped to popularize the term in the United States. As accounts of the Holocaust expanded to include non-Jewish victims, Shoah retained its meaning as the Nazi genocide of the Jews. The Nazis used the phrase "Final Solution to the Jewish Question" (die Endlösung der Judenfrage).
Most Holocaust historians define the Holocaust as the Nazi German policy, enacted between 1941 and 1945, to exterminate the European Jews. In Teaching the Holocaust (2015), Michael Gray offers three definitions. The first refers to the persecution and murder of Jews by the Nazis and their collaborators between 1933 and 1945; this definition views the events of Kristallnacht in Germany in 1938 as an early phase of the Holocaust. The second focuses on the systematic mass murder of Jews by the Nazis and their collaborators between 1941 and 1945; this acknowledges the shift in German policy in 1941 toward the extermination of the Jewish people. The third and broadest definition embraces the persecution and murder of several groups by the Nazis and their collaborators between 1933 and 1945; this includes all the Nazis' victims, but it fails, Gray writes, to acknowledge that only the Jewish people were singled out for annihilation. Donald Niewyk and Francis Nicosia, in The Columbia Guide to the Holocaust (2000), favour a definition that focuses on the Jews, Roma, and Aktion T4 victims: "the systematic, state-sponsored murder of entire groups determined by heredity. This applied to Jews, Gypsies, and the handicapped."
The logistics of the mass murder turned the country into what Michael Berenbaum called "a genocidal state". Bureaucrats identified who was a Jew, confiscated property, and scheduled trains that deported Jews. Companies fired Jews and later employed them as slave labour. Universities dismissed Jewish faculty and students. German pharmaceutical companies tested drugs on camp prisoners; other companies built the crematoria. As prisoners entered the death camps, they were ordered to surrender all personal property, which was catalogued and tagged before being sent to Germany for reuse or recycling. Through a concealed account, the German National Bank helped launder valuables stolen from the victims.