Wikipedia's definition arguably includes the non-fictional Hiroshima and Nagasaki:
Terrorism is, in the broadest sense, the use of intentionally indiscriminate violence as a means to create terror, or fear, to achieve a political, religious or ideological aim. It is used in this regard primarily to refer to violence against peacetime targets or in war against non-combatants.
Terrorism is, in the broadest sense, the use of intentionally indiscriminate violence as a means to create terror, or fear, to achieve a political, religious or ideological aim. It is used in this regard primarily to refer to violence against peacetime targets or in war against non-combatants.