A terrorist organization is a group that uses violence and intimidation, often against civilians, to achieve political, ideological, or religious goals. These groups may operate independently or as part of a larger movement, and they often seek to instill fear to influence governments or societies. Terrorist organizations can vary widely in size, structure, and motivation. Some are well-funded and organized, while others may be loosely connected networks. Examples include groups like Al-Qaeda and ISIS, which have gained international attention for their violent actions and extremist ideologies.