Tank is armored fighting vehicle intended as a primary offensive weapon in front-line ground combat.
Tank designs are a balance of heavy firepower, strong armor, and good battlefield mobility provided by tracks and a powerful engine; usually their main armament is mounted in a turret.
Modern tanks are versatile mobile land weapons platforms whose main armament is a large-caliber tank gun mounted in a rotating gun turret, supplemented by machine guns or other ranged weapons such as anti-tank guided missiles or rocket launchers. They have heavy vehicle armor which provides protection for the crew, the vehicle’s munition storage, fuel tank and propulsion systems.
The use of tracks rather than wheels provides improved operational mobility which allows the tank to overcome rugged terrain and adverse conditions such as mud and ice/snow better than wheeled vehicles, and thus be more flexibly positioned at advantageous locations on the battlefield. These features enable the tank to perform well in a variety of intense combat situations, simultaneously both offensively (with direct fire from their powerful main gun) and defensively (as fire support and defilade for friendly troops due to the near invulnerability to common infantry small arms and good resistance against most heavier weapons), all while maintaining the mobility needed to exploit changing tactical situations. Fully integrating tanks into modern military forces spawned a new era of combat: armored warfare.
Until the arrival of the main battle tank, tanks were typically categorized either by weight class (light, medium, heavy or superheavy tanks) or doctrinal purpose (breakthrough-, cavalry-, infantry- or reconnaissance tanks). Some being larger and very heavily armored and with large guns, while others are smaller, lightly armored, and equipped with a smaller caliber and lighter gun. These smaller tanks move over terrain with speed and agility and can perform a reconnaissance role in addition to engaging enemy targets. The smaller, faster tank would not normally engage in battle with a larger, heavily armored tank, except during a surprise flanking manoeuver.
They are a mainstay of modern 20th and 21st century ground forces and a key part of combined arms combat.