These are the new defintions of terrorism from the state department immediately after 9/11/2001.
http://usembassy.state.gov/lahore/wwwhircaterror.html
The debate over the definition of Terrorism is as old as the term itself. There are several elements that run through the many definitions of terrorism. Under United States law terrorism is "the use of force or violence against persons or property in violation of the criminal laws for purposes of intimidation, coercion or ransom." The Federal Bureau of Investigation (FBI) categorizes terrorism in the United States as one of two types--domestic terrorism or international terrorism. Domestic terrorism involves groups or individuals whose terrorist activities are directed at elements of American government or population without foreign direction, while international terrorism involves groups or individuals whose terrorist activities are foreign-based and/or directed by countries or groups outside the United States or whose activities transcend national boundaries. Long a danger to life and property on a local scale, only lately has terrorism been recognized as a strategic threat to the internal stability--and even survival--of countries. Terrorism is now seen as a threat to the security of the whole international community, particularly as terrorists have increasingly shifted from "conventional" to "unconventional" terrorism. Over the past decade unconventional terrorism has come to be regarded the most threatening of all terrorist tactics. This type of terrorism can be categories as follows:
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