noun
ray gun
Science fiction weapon that fires energy beams. The term is straightforward and not commonly used outside of sci-fi contexts.
SF映画で宇宙飛行士が光線銃を撃った。
In the sci-fi movie, the astronaut fired a ray gun.
Compound of 光線 (こうせん, 'light ray') and 銃 (じゅう, 'gun'). A straightforward modern coinage for science fiction weaponry.