COMMON A reign of terror is a period during which there is a lot of violence and killing, especially by people who are in positions of power. The dictator's 17-year reign of terror had ended and the people took to the streets to celebrate their freedom. His victims during a four-month reign of terror included a schoolgirl and a student. Note: The original Reign of Terror was during the French Revolution between April 1793 and July 1794, when many thousands were put to death by the government.