Question

what is the reign of terror

Answer 1

The Reign of Terror (1793–94) was a period of mass executions by which the Paris-based Jacobins secured power through fear against the province-based Girondists after the French Revolution (1789). The Terror famously used the guillotine to behead victims, including Louis XVI and Marie Antoinette. 

Answer 2

The reign of terror is generally described as the term for a destructive and devastative place for a specific area. It means conquering the enemy by showing it it's true fears. In World War 2 when USA dropped nuclear missiles on Hiroshima and Nagasaki it came to be known as the reign of terror because USA wanted to prove that it can use its nuclear weapons and can cause a hell lot of a destruction. It is the indirect attack on fears of other kingdoms or Nations.