What Is or Isn’t Terrorism in Mosul ?

I have a question to the scholars: Linguists, Historians, sociologists and anthropologists.
We all agree that what ISIS have done must be considered as “terrorism”.
And the terrorism is the unlawful use of violence and intimidation, especially against civilians, in the pursuit of political aims.
For Federal Bureau of Investigation, the terrorism is ‘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’.
The United States Code introduces the understanding to the term of terrorism as illegal violence that tries ‘(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 assassination or kidnapping.

ISIS Killed, used violence and intimidation, especially against civilians, in the pursuit of political and religious aims.

My question is: What do you consider killing civilians by airstrikes? demolishing cities? displacing people? hijacking their memories? what do you consider using violence against civilians? what do you consider what happened in Mosul?
What do you call uprooting whole families, killing the whole family and its relatives, eliminate them permanently off the earth?
My cousins, their parents, children, relatives, they were 16 people, all of them were killed by an airstrike on their house.

I really need your answers…

Thanks in advance!
Omar