gamma ray

Gamma rays or gamma-ray (denoted as γ) are forms of electromagnetic radiation (EMR) or light emissions of a specific frequency produced from sub-atomic particle interaction, such as electron-positron annihilation and radioactive decay; most are generated from nuclear reactions occurring within the interstellar medium of space. Gamma rays are generally characterized as electromagnetic radiation, having the highest frequency and energy, and also the shortest wavelength, within the electromagnetic spectrum, i.e. high energy photons. Due to their high energy content, they are able to cause serious damage when absorbed by living cells.
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A type of high-energy radiation that is different from an x-ray.

Noun
1. electromagnetic radiation emitted during radioactive decay and having an extremely short wavelength
(synonym) gamma radiation
(hypernym) electromagnetic radiation, electromagnetic wave, nonparticulate radiation
(part-holonym) electromagnetic spectrum