Definition UK (2000) 1. In this Act "terrorism" means the use or threat of action where-(a) the action falls within subsection (2), (b) the use or threat is designed to influence the government or to intimidate the public or a section of the public, and (c) the use or threat is made for the purpose of advancing a political, religious or ideological cause. 2. Action falls within this subsection if it- (a) involves serious violence against a person, (b) involves serious damage to property, (c) endangers a person's life, other than that of the person committing the action, (d) creates a serious risk to the health or safety of the public or a section of the public, or (e) is designed seriously to interfere with or seriously to disrupt an electronic system. 3. The use or threat of action falling within subsection (2) which involves the use of firearms or explosives is terrorism whether or not subsection (1)(b) is satisfied 4. In this section- (a) "action" includes action outside the United Kingdom, (b) a reference to any person or to property is a reference to any person, or to property, wherever situated, (c) a reference to the public includes a reference to the public of a country other than the United Kingdom, and (d) "the government" means the government of the United Kingdom, of a Part of the United Kingdom or of a country other than the United Kingdom.

Definition USA (2001) the term `domestic terrorism' means activities that(A) involve acts dangerous to human life that are a violation of the criminal laws of the United States or of any State; (B) 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 (C) occur primarily within the territorial jurisdiction of the United States.'.

Definition National (American) Counterterrorism Centre (2005) An incident was included if it was premeditated, prepared by a subnational or clandestine agent, politically motivated, potentially including religious, philosophical, or culturally symbolic motivations; violent; and perpetrated against a non-combatant target. Ordinary criminal activity, genocidal events, and tribal violence were excluded to the great extent practicable. Hate crimes, to the extent that they could be distinguished from terrorist attacks, were also excluded. Terrorists must have initiated an attack for it to have been included. Non-attack or near-miss incidents were not included because of the inherent difficulty in making hypothetical damage assessments. Incidents must also have involved the citizens or territory of more than one country to be judged international.

Definition EU (2002) The Framework Decision is applicable to any terrorist offence: committed or prepared with intent in a Member State; which may seriously damage a country or an international organisation. These offences must be committed with the aim of intimidating people and seriously altering or destroying the political, economic or social structures of a country (murder, bodily injuries, hostage taking, extortion, fabrication of weapons, committing attacks, threatening to commit any of the above, etc.). The above offences may be committed by one or more individuals against one or more countries. The Framework Decision defines a terrorist group as a structured organisation consisting of more than two persons, established over a period of time and acting in concert. Moreover, instigating, aiding, abetting and attempting to commit terrorist offences will also be punishable. To punish terrorist offences, Member States must make provision in their national legislation for: effective, proportionate and dissuasive criminal penalties, which may entail extradition; mitigating circumstances (collaborating with the police and judicial authorities, finding evidence or identifying the other offenders, etc.).

Definition al-Thawid (1987) Terrorism is an act carried out to achieve an inhuman and corrupt (mufsid) objective, and involving threat to security of any kind, and violation of rights acknowledged by religion and mankind. For the sake of clarity, we may add the following points: (1) We have used the term 'human' instead of 'international' for the sake of wider consensus, official or otherwise, so as to emphasize the general human character of the statement. (2) We have introduced the epithet 'corrupt' (mufsid) to connote the attribute accompanying inhuman objectives, i.e. the spreading of corruption in the land, and to include the imperative to avoid such objectives. (3) We have referred to various types of terrorism with the phrase; "security of any kind". (4) We have mentioned the two criteria, i.e. religious and human, first to be consistent with our belief and then to generalize the criterion. (5) As may be noticed, the fact that an operation is violent does not constitute a condition for considering it a case of terrorism. In the light of the above definition, we shall be able to ascertain the nature of one act or another and determine whether it is a case of terrorism. We shall confirm that the definition does not apply to the following: a. acts of national resistance exercised against occupying forces, colonizers and usurpers; b. resistance of peoples against cliques imposed on them by the force of arms; c. rejection of dictatorships and other forms of despotism and efforts to undermine their institutions; d. resistance against racial discrimination and attacks on the latter's strongholds; e. retaliation against any aggression if there is no other alternative.

Definition “dutch ministry of the Interior and Kingdom Relations” (2005) Terrorism is the use or threatened use of violence against people or the causing of serious damage to property that disrupts daily life, with the aim of bringing about social change or influencing political decision-making. The Netherlands employs a broad-based approach in the fight against terrorism. This means that counterterrorism tackles the process that precedes acts of violence as well as the acts themselves. In other words: taking action at the earliest possible stage of the ‘process’ that turns people into terrorists instead of only taking repressive action when an individual becomes an active terrorist. Terrorist acts are preceded by a process of radicalisation. The government’s approach to radicalisation is therefore explicitly linked to the phenomenon of terrorism.

Other definitions of terrorism (in dutch): Definition Dutch “Amnesty International” (2006) Terrorisme is een afschuwelijke aanval uitgevoerd door individuen, groepen of staten tegen de mens (zijn godsdienst, leven, intellect, eigendom en eer). Het omvat alle vormen van intimidatie, schade, bedreiging, doden zonder gerechtvaardigde oorzaak en alles wat verband houdt met om het even welke vorm van gewapende diefstal waardoor de wegen onveilig worden, banditisme, elke daad van geweld of van bedreiging die bedoeld is om een misdadig plan individueel of collectief uit te voeren, met de bedoeling de mensen angst aan te jagen en met afschuw te vervullen door hen te kwetsen of hun levens, vrijheid, veiligheid of omstandigheden aan gevaar bloot te stellen; het kan ook de vorm aannemen van het toebrengen van schade aan het milieu of aan een openbare of private voorziening of het blootstellen van een nationale of natuurlijke rijkdom ('resource') aan gevaar. Definition terrorism L. Bogaert (2006) Er bestaat nog altijd geen eensgezindheid over wat terreur precies inhoudt. Sommige gevallen zijn duidelijk, andere bewegen zich op een moeilijke grens waarbij wie voor de ene een terrorist is, voor de andere een verzets- of vrijheidsstrijder is. Vermits ik het hier wil hebben over wat de Islam zegt over terrorisme, leek het me aangewezen een door Muslims zelf geformuleerde definitie van terrorisme op te zoeken. De 'Islamic Fiqh Council' van Saudi Arabië definieert terrorisme als volgt: "Terrorisme is een afschuwelijke aanval uitgevoerd door individuen, groepen of staten tegen de mens (zijn godsdienst, leven, intellect, eigendom en eer). Het omvat alle vormen van intimidatie, schade, bedreiging, doden zonder gerechtvaardigde oorzaak en alles wat verband houdt met om het even welke vorm van gewapende diefstal waardoor de wegen onveilig worden, banditisme, elke daad van geweld of van bedreiging die bedoeld is om een misdadig plan individueel of collectief uit te voeren, met de bedoeling de mensen angst aan te jagen en met afschuw te vervullen door hen te kwetsen of hun levens, vrijheid, veiligheid of omstandigheden aan gevaar bloot te stellen; het kan ook de vorm aannemen van het toebrengen van schade aan het milieu of aan een openbare of private voorziening of het blootstellen van een nationale of natuurlijke rijkdom ('resource') aan gevaar. Dit zijn allemaal uitingen van onheil in het land, die God aan Muslims verboden heeft te begaan." (Islamic Fiqh Council, Saudi Arabia [1])