Also known as: レールガン, 電磁砲, 电磁炮(武器)
A Gun, typically consisting of two or more long metal rails flanking the launcher (hence the name), that uses electromagnets to fire projectiles with extreme force and speed. The projectiles do not contain explosives, instead relying on their high kinetic energy to inflict damage.
In real life, railguns are still under development to reduce the power input needed to operate the system, and to reduce the wearing of the system for military uses. Railguns are often seen in Science Fiction works due to their advanced design and extreme power.
Not to be confused with Railway Gun. For the manga and anime series, see Toaru Kagaku No Railgun, or Railgun (Misaka Mikoto) for the specific attack done by the main character of the series.