The word “genocide” was first coined by Polish lawyer Raphäel Lemkin in 1944 in his book Axis Rule in Occupied Europe. It consists of the Greek prefix genos, meaning race or tribe, and the Latin suffix cide, meaning killing. Lemkin developed the term partly in response to the Nazi policies of systematic murder of Jewish people during the Holocaust, but also in response to previous instances in history of targeted actions aimed at the destruction of particular groups of people. Later on, Raphäel Lemkin led the campaign to have genocide recognised and codified as an international crime.
Genocide was first recognised as a crime under international law in 1946 by the United Nations General Assembly (A/RES/96-I). It was codified as an independent crime in the 1948 Convention on the Prevention and Punishment of the Crime of Genocide (the Genocide Convention). The Convention has been ratified by 149 States (as of January 2018). The International Court of Justice (ICJ) has repeatedly stated that the Convention embodies principles that are part of general customary international law. This means that whether or not States have ratified the Genocide Convention, they are all bound as a matter of law by the principle that genocide is a crime prohibited under international law. The ICJ has also stated that the prohibition of genocide is a peremptory norm of international law (or ius cogens) and consequently, no derogation from it is allowed.
The definition of the crime of genocide as contained in Article II of the Genocide Convention was the result of a negotiating process and reflects the compromise reached among United Nations Member States in 1948 at the time of drafting the Convention. Genocide is defined in the same terms as in the Genocide Convention in the Rome Statute of the International Criminal Court (Article 6), as well as in the statutes of other international and hybrid jurisdictions. Many States have also criminalized genocide in their domestic law; others have yet to do so.