More Definition

terrorism: "...the systematic use of terror or unpredictable violence against governments, publics, or individuals to attain a political objective. Terrorism has been used by political organizations with both rightist and leftist objectives, by nationalistic and ethnic groups, by revolutionaries, and by the armies and secret police of governments themselves."

Terrorism is defined in the U.S. by the Code of Federal Regulations as: "..the unlawful use of force and violence against persons or property to intimidate or coerce a government, the civilian population, or any segment thereof, in furtherance of political or social objectives." (28 C.F.R. Section 0.85)"

-From this site

and from this BBC article, I found this:

Article 147 of the Fourth Geneva convention defines war crimes as: "Wilful killing, torture or inhuman treatment, including . . . wilfully causing great suffering or serious injury to body or health, unlawful deportation or transfer or unlawful confinement of a protected person, compelling a protected person to serve in the forces of a hostile power, or wilfully depriving a protected person of the rights of fair and regular trial, . . . taking of hostages and extensive destruction and appropriation of property, not justified by military necessity and carried out unlawfully and wantonly."