No matter where we've grown up we've probably heard and read about "terrorists" that we must defend against. The irony is that whatever group was labeled "terrorist" doesn't see themselves that way and very likely labels their oppponents as terrorists whenever violence is inflicted on their people.
Terrorism is a function of the “enemy” - "the other" – the fear they instill in us regarding violence they might unleash on us.
Reminds me of the play/movie "A Delicate Balance” when the old couple comes to the other couple’s house with their suitcases in tow. They say that the "terror" has come to their house and they had to leave. In their case it was death knocking and their fear of that end.