Also, terrorism is the attacking of non-military targets in order to accomplish something other than the death of those targets. The terror that inspires is secondary to whatever the goal actually is, like releasing hostages, gaining a homeland, or what have you. By this definition the attack on the French military and US Marine barracks in Beirut in October 1983 was not terrorism, as the target was military even if the purpose was other than the death of the Marines and paratroopers. Yes, states often sponsor terrorism, although many terrorists are not state-sponsored. Shooting a President to impress Jodie Foster is not terrorism, though, as it was a single target. Shooting dozens of classmates and teachers because you want to, or are bored, or think they deserve it, isn't terrorism either, IMO. But school shootings are a nuisance, too.