Read the passage and answer the following question
War is a terrible evil. It refers to an armed battle between nations. War causes big suffering to the family members of the people who die during the war. During wars, there is massive destruction of property, wealth, trade, industry, etc. It completely upsets the social life of people.

Peace means complete freedom from disturbance. It refers to those times when there is no war or fight among nations. Once the world starts believing that wars are unnecessary and decide to abolish war completely, they will certainly find a way for peaceful co-existence. A human being’s love for peace is universal. A human being is by nature peaceful. War does not furnish proof of the idea that humans are fighting animals. Even the acts of war did not spoil the human’s spontaneous love for peace.

Modern people are threatened by the dreadful inventions of science. But this actual threat is coming not from science but from war, in which the power of science is abused. It is one thing to keep a nation strong and vigorous and save it, it is another thing to infuse a wanton spirit of aggression and destruction into it. The modern nations must truly realize in their heart the full significance of the teaching – ‘For all, they that take to the sword, shall perish with the sword.’ Then and then only shall peace reign in the world.

Which word in the passage is used for 'rule' ? 

Reign 

'Reign' means to rule or to be in charge.