Very high frequency (and therefore very high energy) electromagnetic radiation emitted as a consequence of radioactivity.

A sunbeam seen just after sunset or just before sunrise, caused by a cloud below the horizon and dust particles in the air above the horizon. / A cloud shadow cast on the bright sky.

(optics) A ray that passes through the axis of the optical fiber.

(astronomy) An energetic particle originating outside our solar system. / (astronomy) Cosmic radiation: a stream of cosmic rays.

Any of several very large pelagic rays formerly of the genus Manta, now placed in genus Mobula, with winglike pectoral fins, a long tail, and two fins resembling horns that project from the head.

A stream of alpha particles.

present participle of X-ray

simple past tense and past participle of X-ray

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

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