terrorism vs reign of terror

terrorism and reign of terror both are nouns.

Word	Noun	Adjective	Verb	Adverb
terrorism	Yes	No	No	No
reign of terror	Yes	No	No	No

terrorism (noun)	reign of terror (noun)
the calculated use of violence (or the threat of violence) against civilians in order to attain goals that are political or religious or ideological in nature; this is done through intimidation or coercion or instilling fear	any period of brutal suppression thought to resemble the Reign of Terror in France