This is the from the United States Code regarding the definition:
U.S.C. Title 18 - CRIMES AND CRIMINAL PROCEDURE (govinfo.gov)
§2331. Definitions
As used in this chapter—
(1) the term “international terrorism” means activities that—
(A) involve violent acts or acts dangerous to human life that are a violation of the criminal laws of the United States or of any State, or that would be a criminal violation if committed within the jurisdiction of the United States or of any State;
(B) 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 outside the territorial jurisdiction of the United States, or transcend national boundaries in terms of the means by which they are accomplished, the persons they appear intended to intimidate or coerce, or the locale in which their perpetrators operate or seek asylum;
(2) the term “national of the United States” has the meaning given such term in section 101(a)(22) of the Immigration and Nationality Act;
(3) the term “person” means any individual or entity capable of holding a legal or beneficial interest in property;
(4) the term “act of war” means any act occurring in the course of—
(A) declared war;
(B) armed conflict, whether or not war has been declared, between two or more nations; or
(C) armed conflict between military forces of any origin; and
(5) the term “domestic terrorism” means activities that—
(A) involve acts dangerous to human life that are a violation of the criminal laws of the United States or of any State;
(B) 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.
(Added Pub. L. 102–572, title X, §1003(a)(3), Oct. 29, 1992, 106 Stat. 4521; amended Pub. L. 107–56, title VIII, §802(a), Oct. 26, 2001, 115 Stat. 376.)
The key points which are common to the definitions of both international and domestic terrorism are violent acts dangerous to human life which:
(B) 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
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I guess what strikes me about this is that, whatever the apparent intended goals of terrorism might be, they don't really seem to work.