The term is simply used to name "the others" while inducing the emotional response among "our" population. The terrorists are always those who are against "us" and "we" can never do the "terrorism" even when "we" do "the calculated use of violence or threat of violence to attain goals that are political, religious, or ideological in nature...through intimidation, coercion, or instilling fear."

The religions would call these "others" "the unbelievers," of course. Even though everybody in the world doesn't believe in most of the gods of the world. The "terrorists" is used as something like "the evil others."

A case study: The start of the WWII (in Europe) with Germany attacking Poland:

https://en.wikipedia.org/wiki/Invasion_of_Poland

"The invasion was referred to by Germany as the 1939 Defensive War since Hitler proclaimed that Poland had attacked Germany and that "Germans in Poland are persecuted with a bloody terror and are driven from their homes. The series of border violations, which are unbearable to a great power, prove that the Poles no longer are willing to respect the German frontier.""

It's always "them."

Even as internationally "agreed":

http://www.beyondintractability.org/essay/terrorism-defined

"Although the longest, the United Nations' definition is arguably the broadest and mostly serves to individualize the act, which, like the State Department, disregards nations as possible agents of terrorism. At the time the declaration was registered in April 2002, 132 of the 180 parties had signed the resolution. What is most interesting about the United Nations Declaration made by the General Assembly, is not necessarily the definition itself, but the 'declarations', 'reservations', 'understandings', and subsequent 'objections' made by the parties (See Appendix). Take notice how Yemen did not sign the declaration on the basis that, as a nation, it did not want to relay the impression that it was recognizing Israel's existence. Many of the countries signed the declaration, but not before declaring that it did not apply to them because they were unbound for one reason or another."

"United States signed with the following reservation: "(a) pursuant to Article 24 (2) of the Convention, the United States of America declares that it does not consider itself bound by Article 24 (1) of the Convention; and

(b) the United States of America reserves the right specifically to agree in a particular case to follow the arbitration procedure set forth in Article 24 (1) of the Convention or any other procedure for arbitration."

Understandings:

"(1) EXCLUSION OF LEGITIMATE ACTIVITIES AGAINST LAWFUL TARGETS. The United States of America understands that nothing in the Convention precludes any State Party to the Convention from conducting any legitimate activity against any lawful target in accordance with the law of armed conflict.

(2) MEANING OF THE TERM 'ARMED CONFLICT'. The United States of America understands that the term 'armed conflict' in Article 2 (1) (b) of the Convention does not include internal disturbances and tensions, such as riots, isolated and sporadic acts of violence, and other acts of a similar nature."

With regard to the declaration made by the Jordan upon ratification:

"The Government of the United States of America, after careful review, considers the statement made by Jordan relating to paragraph 1 (b) of Article 2 of the Convention (the Declaration) to be a reservation that seeks to limit the scope of the offense set forth in the Convention on a unilateral basis. The Declaration is contrary to the object and purpose of the Convention, namely, the suppression of the financing of terrorist acts, irrespective of where they take place or who carries them out.""