Let us begin with the dictionary definition of terror -- “intense, overpowering fear” -- and of terrorism -- “the use of terrorizing methods of governing or resisting a government.” This simple definition has the virtue of fairness; it focuses on the use of coercive violence and its effects on the victims of terror without regard to the status of the perpetrator. Terrorism does not refer to the mutual fear of armed adversaries, but only to acts of intimidating and injuring unarmed, presumably innocent civilians. Therein lies the revulsion over terrorist acts. This definition leaves out the question of motivation. Motives have varied, and so have methods. Many terrorists in our time have no identifiable goals.