How would you define terrorism?

Organized governments.

Extreme religious or political insanity. That's why I HATE religions and avoid politics.

like democracy every country has its own definition of terrorism.

Look in a dictionary - the definition is pretty clear. I do not understand why everyone is in such a panic about whether this is "terrorism" or not. We need to understand the boys' motives, and that should tell us the answer.

There are legal definitions for terrorism however it means different things to different people throughout the world. Thus nowadays it probably amounts to self-glorification with bullying solely on a very large scale. After all these low-life cowards have powerful weapons and fighters who embrace death as martyrdom. Therefore nothing is worse than a dangerous miserable coward who is most likely a religious fanatic and believes that he has nothing to lose.

The use of physical or economic violence with a motive of instilling fear and terror in a population in order to coerce or subjugate them to the interests, desires or convictions of the perpetrator.

And yes, state terrorism is included in this definition.

This is a very sensitive topic that may lead to a big misunderstanding when comments are given.

British English: The performing of acts of violence which are designed to induce terror.

American English: The performing of acts of violence which are designed to induce terror when they are neither approved of or sponsored by the U.S. government.