radiation
n. uncountablen. energy that travels through space as waves or tiny particles. It can come from things like the sun, X-ray machines, or nuclear power.
n. the emission or transmission of energy in the form of waves or particles through space or a material medium. Often used in contexts involving electromagnetic waves or nuclear decay.
The sun sends out radiation that can burn your skin.
Doctors use lead aprons to protect themselves from radiation when they take X-ray images of patients.
While low levels of background radiation are naturally present in the environment, prolonged exposure to high-energy ionising sources can cause significant damage to living tissue and DNA.
Borrowed from Latin radiatio, radiationis. By surface analysis, radiate + -ion.
Uncountable in its general scientific sense; occasionally used as a countable noun in physics when referring to specific types or instances of emission.