A railgun is a type of large kinetic weapon, typically used as artillery, as ship-mounted weaponry, or anti-vehicle armament. Railguns use a series of superconductive electromagnets to accelerate a powerful and dense metal slug typically made of a dense metal like depleted uranium, tungsten, or even impervium, using the sheer velocity and mass of the round to punch through armor. Railguns are rarely used as personal weapons due to their sheer size, and are almost always found as artillery emplacements or as ship weapons.
A very large railgun, often mounted as the primary spine weapon of a ship can be called a mass driver.