A more thorough explanation:

A state of war is when a war has been declared or when there is armed conflict happening. It can be between different countries or within the same country.

For example, the Gulf War was a state of war between Iraq and a coalition of countries led by the United States. The American Civil War was a state of war within the United States between the Union and the Confederacy.

Even if there is no fighting happening, a state of war can still exist. For instance, the United States and Japan were in a state of war for seven years after World War II ended until they signed a treaty to formally end it.

Other types of wars include:

• Civil war: an internal armed conflict between people of the same nation
• Imperfect war: a limited war in terms of places, persons, and things
• Mixed war: a war between a nation and private individuals
• Perfect war: a war involving an entire nation against another
• Private war: a war between private persons
• Public war: a war between two nations under the authority of their respective governments
• Solemn war: a war formally declared by one country against another

War can also refer to a dispute or competition between adversaries, such as fare wars in the airline industry. It can also be a struggle to solve a pervasive problem, like America's war against drugs.

War crimes are actions that violate international laws governing the conduct of international armed conflicts. Examples include killing hostages, abusing civilians in occupied territories, abusing prisoners of war, and causing unnecessary devastation.

Understanding the state of war is important because it can have significant consequences for individuals and nations involved. It can lead to loss of life, destruction of property, and long-lasting political and social effects.