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Meaning & use

radiation

noun·Academic

Last updated

UK/ˌreɪ.diˈeɪ.ʃən/
US/ˌreɪ.diˈeɪ.ʃən/

Meanings

  1. noununcountablephysics

    Energy that travels through space or matter as waves or particles, such as light, heat, radio waves, or nuclear emissions.

    Grammar: Usually uncountable; do not add a plural in general use.

    Patterns

    • emit radiation
    • exposure to radiation
    • radiation from something

    Visible light is one form of electromagnetic radiation.

    The sensor measures radiation from the sun.

    Heat moves from the fire by radiation as well as by air currents.

  2. noununcountabletechnical

    High-energy nuclear emissions that can damage living tissue and matter.

    Grammar: Often modified by ionizing, nuclear, or background in news and safety contexts.

    Patterns

    • nuclear radiation
    • ionizing radiation
    • radiation leak or levels
    • radiation sickness

    Workers wore protective suits because of possible radiation exposure.

    The authorities monitored radiation levels after the accident.

    A thick concrete wall can shield against some nuclear radiation.

Common combinations

exposure to radiation
Long exposure to radiation requires strict medical monitoring.
emit radiation
Hot objects emit infrared radiation even in complete darkness.
radiation therapy
Radiation therapy can target cancer cells while sparing nearby tissue.
background radiation
Background radiation is always present from natural and human-made sources.

Synonyms and how they differ

emission
The act or product of sending something out; radiation specifically concerns energy traveling as waves or particles.
irradiation
The process of exposing something to radiation, not the energy itself.

Opposites

absorption

Word family

radiate verb
To send out energy, heat, light, or a strong feeling.
radiant adjective
Sending out light or heat, or shining with happiness.
radioactive adjective
Containing unstable atoms that release radiation.
radioactivity noun
The property of releasing radiation from unstable nuclei.

Commonly confused: radiation or radioactivity? radiation or radiator?

radiation vs radioactivity

Radioactivity is a property of unstable material; radiation is the energy that material releases.

radiation vs radiator

A radiator is a device that heats a room or cools an engine; it is not the general physics term.

Practice

Which sentence is correct in a physics context?

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