Despite decades of efforts by the international community against terrorism, especially after the terrorist attacks of 9/11-2001, two decades later, it has not succeeded in suppressing it. Terrorism, on the other hand, is increasingly undermining international peace and security. What the international community has become skeptical about and challenged in the present age through the commission of terrorist crimes is the lack of a proper and universal definition in identifying all aspects and manifestations of this phenomenon. The definition has made the distinction between legitimate and liberating struggles and the use of terrorism and the possibility of abusing the right to self-defense. However, international conventions and even counterterrorism zones, despite providing numerous instances of terrorist offenses, have not yet come up with a single and comprehensive definition of terrorism; While we can refer to war and its definition in the four Geneva Conventions. In addition, the lack of a definition of terrorism can be traced to the lack of a clear structure and framework for achieving consensus between governments and international organizations, according to which a common global definition and approval of terrorism can substantially facilitate the counter-terrorism process.