A fuel tank (or petrol tank) is a safe container for flammable fluids. Though any storage tank for fuel may be so called, the term is typically applied to part of an engine system in which the fuel is stored and propelled (fuel pump) or released (pressurized gas) into an engine. Fuel tanks range in size and complexity from the small plastic tank of a butane lighter to the multi-chambered cryogenic Space Shuttle external tank.
Armoured warfare or tank warfare is the use of armoured fighting vehicles in modern warfare. It is a major component of modern methods of war. The premise of armoured warfare rests on the ability of troops to penetrate conventional defensive lines through use of manoeuvre by armoured units.
Much of the application of armoured warfare depends on the use of tanks and related vehicles used by other supporting arms such as infantry fighting vehicles and self-propelled artillery, as well as mounted combat engineers and other support units. The doctrine of armoured warfare was developed to break the static nature of World War I trench warfare on the Western Front, and return to the 19th century school of thought that advocated manoeuvre and "decisive battle" outcomes in military strategy.