Firepower is the military capability to direct force at an enemy. (It is not to be confused with the concept of rate of fire, which describes the cycling of the firing mechanism in a weapon system.) Firepower involves the whole range of potential weapons. The concept is generally taught as one of the three key principles of modern warfare wherein the enemy forces are destroyed or have their will to fight negated by sufficient and preferably overwhelming use of force as a result of combat operations.
Through the ages firepower has come to mean offensive power applied from a distance, thus involving ranged weapons as opposed to one-on-one close quarters combat. Firepower is thus something employed to keep enemy forces at a range where they can be defeated in detail or sapped of the will to continue. In the field of naval artillery, the weight of a broadside was long used as a figure of merit of a warship's firepower.