The term ‘terrorism’ is among the most frequently used words. It accompanies us on an everyday basis. It is apparently understood in a similar manner throughout the world, but it is actually interpreted and defined in different ways. “All vogue words appear to share a similar fate: the more experiences they pretend to make transparent, the more they themselves become opaque”. Terrorism is no exception to that rule. This has become particularly apparent following the events of September 11, Bali, Madrid and London. Terrorism is characterized not only by its manifold nature and complexity but also by the problem with its definition.