Genocide is defined as the planned and systematic destruction of particular national, religious, ethnic, or political groups, characterized by acts such as mass killings and severe bodily or mental harm. The concept has evolved since its formal definition in 1943, expanding to include various groups beyond the original focus on racial and ethnic categories. The document highlights historical examples of genocide, particularly the Rwandan genocide, and emphasizes the importance of addressing and educating about these atrocities as critical human rights issues.