§ 2331 defines "international terrorism" and "domestic terrorism" for purposes of Chapter 113B of the Code, entitled "Terrorism":
"International terrorism" means activities with the following three characteristics:
Involve violent acts or acts dangerous to human life that violate federal or state law;
Appear to be intended (i) to intimidate or coerce a civilian population; (ii) to influence the policy of a government by intimidation or coercion; or (iii) to affect the conduct of a government by mass destruction, assassination, or kidnapping; and

occur primarily outside the territorial jurisdiction of the U.S., or transcend national boundaries in terms of the means by which they are accomplished, the persons they appear intended to intimidate or coerce, or the locale in which their perpetrators operate or seek asylum. Media spectacle
A definition proposed by Carsten Bockstette at the George C. Marshall European Center for Security Studies, underlines the psychological and tactical aspects of terrorism:

Terrorism is defined as political violence in an asymmetrical conflict that is designed to induce terror and psychic fear (sometimes indiscriminate) through the violent victimization and destruction of noncombatant targets (sometimes iconic symbols). Such acts are meant to send a message from an illicit clandestine organization. The purpose of terrorism is to exploit the media in order to achieve maximum attainable publicity as an amplifying force multiplier in order to influence the targeted audience(s) in order to reach short- and midterm political goals and/or desired long-term end states. Terrorists attack national symbols, which may negatively affect a government, while increasing the prestige of the given terrorist group or its ideology.
Others, like Roderick Hindery, have sought to discern profiles in the propaganda tactics used by terrorists. Some security organizations designate these groups as violent non-state actors. A 2007 study by economist Alan B. Krueger found that terrorists were less likely to come from an impoverished background (28 percent versus 33 percent) and more likely to have at least a high-school education (47 percent versus 38 percent). Another analysis found only 16 percent of terrorists came from impoverished families, versus 30 percent of male Palestinians, and over 60 percent had gone beyond high school, versus 15 percent of the populace.A study into the poverty-stricken conditions and whether terrorists are more likely to come from here,show that people who grew up in these situations tend to show aggression and frustration towards others. This theory is largely debated for the simple fact that just because one is frustrated,does not make them a potential terrorist.To avoid detection, a terrorist will look, dress, and behave normally until executing the assigned mission. Some claim that attempts to profile terrorists based on personality, physical, or sociological traits are not useful. The physical and behavioral description of the terrorist could describe almost any normal person. the majority of terrorist attacks are carried out by military age men, aged 16 to 40. Non-state groups
Groups not part of the state apparatus of in opposition to the state are most commonly referred to as a "terrorist" in the media.