The goal is to hurt civilians, creating fear and confusion.
"Fear is the outcome that a terrorist wants. They want people being scared and in being scared, they want them to change their behavior," Dr. Jeremi Suri, the Mack Brown Distinguished Chair for Leadership in Global Affairs at UT.
Suri said, "Using the T-word, using the "terrorism" word is basically saying, you might see more of this. We don't have control over it."
At first, there was some hesitation by officials to call the events in Boston, an act of terror, but a day after two explosions ripped through the finish line at the Boston marathon, wounding nearly 200 and killing three people, the President said this; "This was a heinous and cowardly act, and given what we now know about what took place, the FBI is investigating it as an act of terrorism."
Many people, like former Fort Hood Police Sergeant Kimberly Munley, believe the 2009 mass shooting at the U. S. military base in Killeen, should also be classified as "terrorism" instead of "work place violence."
"The victims of the massacre have not been taken care of. They've been neglected by the government," said Munley. "If it gets reclassified as a "terrorist attack," I don't receive any additional benefits,"
"What makes the Fort Hood shooting a little different is that the individual who did it was apparently targeting particular people and had a particular grievance that he felt was going to be addressed, in some way, by this. But, I think there are terroristic elements of it," Suri said. "If you say it's an individual incident, perpetrated by a soldier who had psychological difficulties, then it doesn't sound like it's going to be repeated."
Acts of terror can be carried out by individuals or groups.
"The more it's a group, the more there could be other events like this," Suri added.
The threats can also be foreign or domestic.
"It's most often people internally and...One of the things that's most true about all kinds of murder is you're most threatened by those who are closest to you," said Suri. "People who commit these acts are not committing them because they're victims, but they're committing them because somehow society has not integrated them or has not anticipated what they're doing."
Suri adds most terrorists are not copycats, so we, as a society, need to look to the next places and events that are most vulnerable.