(science fiction) A fictional beam of radiation that can kill.

(science fiction) A fictional weapon that emits harmful rays.

Alternative spelling of gamma ray

(engineering) Electromagnetic waves with frequencies intermediate between, and sharing properties of both, short radio waves and long IR optical waves. This region is defined variously as between 0.1 - 10 THz, 0.3-3 THz or 0.3-30 THz.

Alternative spelling of ray gun

Alternative spelling of death ray

(computer graphics) A technique that produces realistically shaded images by projecting imaginary light rays to determine which parts of an object should be illuminated.

(of fish) In the Actinopterygii taxonomic class of fish, all having in common lepidotrichia (a kind of fin made of webs of skin supported by bony or horny spines).

(informal) The Blu-ray Disc format. / (informal) A Blu-ray Disc.

(physics) An electron ejected by recoil when a rapidly moving alpha particle or other charged particle passes through matter.