Allies: During World War II, the group of nations including the United States, Britain, the Soviet Union, and the Free French, who joined in the war against Germany and other Axis countries.

Bystander: One who is present at some event without participating in it.

Final Solution (The final solution to the Jewish question in Europe): A Nazi euphemism for the plan to exterminate the Jews of Europe.

Gestapo /geshtahpoh/: Acronym for Geheime Staatspolizei /gehaime shtahtspolitsai/, meaning Secret State Police. Prior to the outbreak of war, the Gestapo used brutal methods to investigate and suppress resistance to Nazi rule within Germany. After 1939, the Gestapo expanded its operations into Nazi-occupied Europe.

Ghettos: The Nazis revived the medieval term ghetto to describe their device of concentration and control, the compulsory "Jewish Quarter." Ghettos were usually established in the poor sections of a city, where most of the Jews from the city and surrounding areas were subsequently forced to reside. Often surrounded by barbed wire or walls, the ghettos were sealed. Established mostly in eastern Europe (e.g., Lodz, Warsaw, Vilna, Riga, or Minsk), the ghettos were characterized by overcrowding, malnutrition, and heavy labor. All were eventually dissolved, and the Jews murdered.

Guerrilla warfare: Fighting in which small independent bands of soldiers harass an enemy through surprise raids, attacks on communications and the like.

Holocaust: Derived from the Greek holokauston which meant a sacrifice totally burned by fire. Today, the term refers to the systematic planned extermination of about six million European Jews and millions of others by the Nazis between 1933-1945.

Partisans: Irregular forces which use guerrilla tactics when operating in enemy-occupied territory. During the Holocaust, partisans operated secretly in their efforts to assist Jews and others persecuted by the Nazis.

Pogrom: An organized and often officially encouraged massacre of or attack on Jews. The word is derived from two Russian words that mean "thunder."

Righteous Gentiles: Non-Jewish people who, during the Holocaust, risked their lives to save Jewish people from Nazi persecution. Today, a field of trees planted in their honor at the Yad Vashem Holocaust Memorial in Jerusalem, Israel, commemorates their courage and compassion.

Hannah Sennesh: A Palestinian Jew of Hungarian descent who fought as a partisan against the Nazis. She was captured at the close of the war and assassinated in Budapest by the Nazis.

Underground: Organized group acting in secrecy to oppose government, or, during war, to resist occupying enemy forces.

Raoul Wallenberg: A Swedish diplomat who deliberately stationed himself in Hungary during the war to save Hungarian Jews from their deaths.