Since the 1970s, many researchers have proposed typologies to sort the phenomenon of terror into different categories and to divide terror organizations into groups based on various characteristics of their activities. These typologies were designed to facilitate understanding of the phenomenon of terror and of terror organizations' processes, structures and operative methods. They relied on a variety of diagnostic criteria such as: motives for using terror, targets of the attacks, terrorists' demands, organizational structure; arenas of operation; and more. This article surveys major typologies of terror, notes the differences between them, presents a model to combine the different classifications of the typologies into a single typology, and proposes a new typology that sorts terror organizations by the variables that limit their activities. The proposed typology makes it possible to analyze terror organizations' behavior and even to forecast their reactions to a situation in which they are attacked by the enemy state - the boomerang effect.