The term Bloodlands refers to the territories caught between Nazi Germany and the Soviet Union during the period from 1933 to 1945, where the regimes of Hitler and Stalin committed mass killings. Snyder defines this area geographically as consisting of Poland, Ukraine, Belarus, the Baltic States (Lithuania, Latvia, Estonia), and western Russia. Throughout the book, Bloodlands is not just a physical space but a conceptual framework for understanding the intersection of two totalitarian powers and the catastrophic human suffering they caused.

Collectivization was a policy pursued by Stalin in the Soviet Union, aimed at consolidating individual landholdings and labor into collective farms. Snyder describes it as a cause of widespread famine, particularly in Ukraine, resulting in millions of deaths. The term functions in the book as an example of how ideological policies can lead to mass human suffering and as a critical component of Stalin’s broader strategy of control and transformation of the Soviet countryside.

Einsatzgruppen were mobile killing units of the Nazi security apparatus that played a central role in the mass murder of Jews, Roma, and political commissars in the Soviet Union and Eastern Europe. Snyder discusses their deployment following the German invasion of the Soviet Union in 1941, highlighting their responsibility for mass shootings, particularly in the Bloodlands.