“Atrocity crimes” is an umbrella term that refers to the four categories of crimes that constitute violations of International Criminal Law: crimes against humanity, genocide, war crimes and, increasingly, the crime of aggression. It’s a relatively new term coined some 20 years ago. Prior to this, “war crimes” was used generically to describe these categories of international crimes, and it remains commonly used today as an umbrella term. Technically, however, war crimes are a specific category of international crimes committed in armed conflict against persons protected by the Geneva Conventions, including civilians and prisoners of war. To avoid the confusion created by the dual use of “war crimes” in both the generic sense and in reference to the specific, technical violation, “atrocity crimes” is now the preferred umbrella term.

Below are some quick definitions of other key terms. Neither the list nor the definitions are meant to be exhaustive but rather serve as an introduction. More information about each term can be found in the links provided and by visiting the International Committee of the Red Cross database.

Genocide: Acts committed with the intent to destroy, in whole or in part, a national, ethnic, racial or religious group. Importantly, it requires proving the intent of the perpetrators to destroy a specific group.

Crimes Against Humanity: A widespread or systematic attack against the civilian population. Unlike war crimes, a state of armed conflict does not need to exist. Examples include persecution, murder, torture, deportation, rape, enslavement, enforced disappearance and other similar inhumane acts intentionally causing great suffering, serious injury to body or to mental or physical health.

War of Aggression: The use of armed force by a State against the sovereignty, territorial integrity or political independence of another State, or in any other manner inconsistent with the Charter of the United Nations.

Violations of the Law and Customs of War: Commonly referred to as “war crimes” under Article 3 of the Geneva Conventions and also part of Customary International Law. It includes crimes such as use of poisonous weapons, wanton destruction of cities or towns, attacks on undefended towns or buildings, and seizure or destruction of cultural heritage or educational sites and plunder.

• Grave Breaches of the Geneva Conventions: Refers specifically to serious forms of war crimes listed in common articles of the Geneva Conventions. They include willful killing, torture, causing great suffering or serious injury to body or health, extensive destruction and appropriation of property not militarily justified, compelling a civilian or POW into military service of a hostile power or deprivation of a fair trial, deportation or forced transfer, and civilian hostage-taking.

Command Responsibility: Individual military commanders, or political leaders, can be held responsible for their failure to exercise proper control over subordinates who commit atrocity crimes.

Conflict-Related Sexual Violence (CRSV): Any form of sexual violence perpetrated in conflict, including rape, sexual slavery and forced prostitution. Victims are typically targeted for their actual or perceived affiliation with an ethnic, religious or political group.

Customary International Law (CIL): Legal obligations stemming from common, accepted practice rather than a treaty. In the context of armed conflict, it fills gaps in treaty law.

International Humanitarian Law (IHL): The “laws of war” were first codified in 1864. The Four Geneva Conventions of 1949 and the Additional Protocols of 1977 are the modern cornerstone of IHL. Their provisions place limits on conduct during armed conflict, for example by protecting civilians and regulating treatment of prisoners of war.

Codifications of International Criminal Law (ICL): A body of law that defines individual criminal responsibility, typically in the context of armed conflict, for the “core crimes” of genocide, crimes against humanity, war crimes and the crime of aggression. Key legal instruments include the Geneva Conventions and Additional Protocols, the Rome Statute, which created the International Criminal Court, the Genocide Convention and the Nuremberg Charter.

International Human Rights Law (IHRL): The Universal Declaration of Human Rights (1948) defined human rights law at the international level for the first time. Although IHL and IHRL share some similar provisions, such as a prohibition on torture and ill-treatment, they differ in one important aspect: IHL applies in situations of armed conflict whereas IHRL applies at all times.

Universal Jurisdiction: A legal principle allowing national courts to prosecute individuals for crimes against humanity, genocide and war crimes that have been committed anywhere in the world. It seeks to promote accountability by depriving perpetrators of safe havens.

Open-Source Intelligence (OSINT): Publicly available information or resources used to gather and analyze information. Sources can include satellite imagery, social media channels, public records and news media.