Conventional warfare means a form of warfare conducted by
using conventional military weapons and battlefield tactics between two or more nation-states in open confrontation. The forces on each side are well-defined, and fight each other using weapons that primarily target the opposing army. It is normally fought means other than with chemical, biological, or nuclear weapons. In other words without the use of weapons of mass destruction.
The general purpose of conventional warfare is to destroy the opponent's military force, thereby negating his ability to engage in conventional warfare. Without a conventional force, the defender is then unable to prevent devastating attacks upon his nation-state, and can thus be forced to capitulate. However the defender may be willing to accept the consequences of such attacks, and resort to unconventional warfare in order to ultimately achieve his goals.
The overwhelming majority of wars have been conducted using the means of conventional warfare. Biological warfare has not been used since the 19th century (though it is possible that the recent anthrax attacks in the United States were bioterrorism), and chemical warfare has been used only a few times. Nuclear warfare has only occurred once with the United States bombing the Japanese cities of Hiroshima and Nagasaki to end World War II in the Pacific.