radiation

UK/ˌɹeɪ.diˈeɪ.ʃən/US/ˌɹeɪ.diˈeɪ.ʃən/

nounB2Common in everyday speech and writing · #2,803 of 15,258neutral

Other forms: radiations

Radiation is invisible energy rays, some useful in hospitals and some deadly. Radiation therapy, background radiation, radiation dose.

The important split is between ionising radiation, which breaks molecules and damages cells, and non-ionising, which does not — light and radio are radiation and are not the danger. Everybody receives a background dose all the time, mostly from rocks and from space. Note that the Latin means a ray.

Definitions of radiation

1nounradiationEnergy travelling as rays or particles.B2
“Doctors use radiation to treat some kinds of cancer.”

radiation is a form of energy.

Where it comes from

Latin radiatio comes from radiare, to emit rays, from radius, a ray or spoke. Radius and radio come from the same ray.

Latin
radiatio
English, today
radiation

Learned borrowing from Latin radiatio. Borrowed from Latin radiatio. by surface analysis, radiate + -ion.

Etymology from Wiktionary, CC BY-SA

Practised in Science & Space

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radiation in the wild

Unlike the plasma, these atoms could not scatter thermal radiation by Thomson scattering, and so the universe became transparent.
Cosmic microwave background
Almost all black-body radiation from objects near room temperature is in the IR band.
Infrared
Most common cancer types can be treated with radiation therapy in some way.
Radiation therapy
However X-rays are ionizing radiation and exposure can be hazardous to health, causing DNA damage, cancer and, at higher intensities, burns and radiation sickness.
X-ray
The higher the ionising effect, the greater the damage to living tissue, but also the lower the penetrating power of the radiation through matter.
Beta particle

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From Wikipedia, CC BY-SA 4.0. These sentences were written by other people about their own subjects; they are here to show the word at work, not as anybody’s opinion.

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