An atrocity (from the Latin atrox, "atrocious", from Latin ater = "matte black" (as distinct from niger = "shiny black")) is a term used to describe crimes ranging from an act committed against a single person to one committed against a population or ethnic group.

In general use, an atrocity or massacre designates a politically or ethnically motivated killing of civilians. In international law, more precise terms are war crime and crime against humanity.

An atrocity can be a single specific event, or a series of events, or can refer to genocide. The defining characteristic of an atrocity is its brutal or systematic nature. It is an act of killing that is in violation of most traditional moral principles, although some societies do not condemn such behavior. Often, hostilities exceed the legitimate mandate of killing enemy combatants to include attacks upon unarmed or otherwise non-combative peoples. Thus, nearly every culture has in its history acts of killing which are atrocities.

See also

• Genocide
• Terrorist incidents
• Collateral damage
• Serial killing
• Murder
• Torture
• List of massacres
• Unit 731
• Rwandan Genocide
• Great Purge
• Holocaust
• Native American massacres