Actually in the US the definition of what is or isn't a terrorist act is defined in 2 ways... one on a State level and another Federally.
In Nevada the State Statute defines an act of terrorism as : “act of terrorism" means any act that involves the use or attempted use of sabotage, coercion or violence which is intended to cause
great bodily harm or death to the general population”.
This seems to fit the bill for what took place in Las Vegas. Please note that there is no universally agreed upon definition of the word terrorism.
the UN members don't have a single definition either.
Also have a look at the varying definitions of terrorism:
United States
The United States has defined terrorism under the Federal Criminal Code. Title 18 of the United States
Code defines terrorism and lists the crimes associated with terrorism. In Section 2331 of Chapter 113(B),
defines terrorism as: “…activities that involve violent… or life-threatening acts… that are a violation of the
criminal laws of the United States or of any State and… appear to be intended (i) to intimidate or coerce a
civilian population; (ii) to influence the policy of a government by intimidation or coercion; or (iii) to affect
the conduct of a government by mass destruction, assassination, or kidnapping; and…(C) occur primarily
within the territorial jurisdiction of the United States…”
a) US Patriot Act of 2001: terrorist activities include:
• threatening, conspiring or attempting to hijack airplanes, boats, buses or other vehicles.
• threatening, conspiring or attempting to commit acts of violence on any "protected" persons,
such as government officials
• any crime committed with "the use of any weapon or dangerous device," when the intent of the
crime is determined to be the endangerment of public safety or substantial property damage
rather than for "mere personal monetary gain[/B]
b) FBI definition of terrorism: The unlawful use of force or 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.
U.S. Army Manual definition terrorism is the "calculated use of unlawful violence or threat of unlawful
violence to inculcate fear. It is intended to coerce or intimidate governments or societies ... [to attain]
political, religious, or ideological goals." U.S. Army Field Manual No. FM 3-0, Chapter 9, 37 (14 June
2001).
c) Department of Defense Dictionary of Military Terms defines terrorism as: The calculated use of
unlawful violence or threat of unlawful violence to inculcate fear; intended to coerce or to intimidate
governments or societies in the pursuit of goals that are generally political, religious, or ideological.