1Heating power or thermal power — the strength or capacity of heat produced by combustion or heating, often referring to output in heating, cooking, or power generation.
このストーブは火力が強いので暖まるのが早い。
This stove has strong heating power, so it warms up quickly.
火力発電所は石炭やガスを燃やして電力を生み出す。
Thermal power plants burn coal or gas to generate electricity.
料理の火力を調整して焦げ付きを防いだ。
I adjusted the heat so the food wouldn't burn.
2In a military context, firepower — the offensive capability of weapons and forces, such as the rate and intensity of fire.
敵の火力が強く、前進は難しかった。
The enemy's firepower was strong, so advancing was difficult.
最新の装備で部隊の火力が向上した。
With the latest equipment, the unit's firepower improved.