Definition of radioactive in US English:



  • Emitting or relating to the emission of ionizing radiation or particles.

    ‘radioactive decay’
    ‘the water was radioactive’
    • ‘The periodic table has since been expanded to 81 stable and 31 radioactive elements.’
    • ‘In reality all they did was make my blood radioactive before taking gamma photographs.’
    • ‘He explained spent nuclear fuel is not radioactive waste because it can be reused.’
    • ‘They fill up the thyroid gland and stop it from absorbing any radioactive iodine released by the reactor.’
    • ‘This three-year project was to lead to the discovery of the causes of radioactive emissions.’
    • ‘Depleted uranium is a radioactive heavy metal, which is also chemically toxic.’
    • ‘Part of the problem is that as the radioactive substance decays, most of the electrons miss the silicon surface.’
    • ‘Carbon - 14 is radioactive and it is this radioactivity which is used to measure age.’
    • ‘If a nucleus has too many protons for its number of neutrons, it will be radioactive.’
    • ‘They also debated earnestly over how polluted and radioactive they thought the Caspian's waters were.’
    • ‘It relies on an analysis of how much of a radioactive isotope has decayed into its daughter isotope.’
    • ‘When a fuel rod is spent and removed from the reactor, it is hot and highly radioactive.’
    • ‘They realized that the particles emitted by radioactive elements as they decay are in fact little bits of the atomic nuclei.’
    • ‘The specific activity of the radioactive thiamine was the same for each concentration used.’
    • ‘The C-urea breath test detects current infection and is not radioactive.’
    • ‘Radon decays to form tiny radioactive particles, some of which remain suspended in the air.’
    • ‘Nuclear fusion produces no greenhouse gas emissions and only low levels of radioactive waste.’
    • ‘It is so hot and radioactive that the miners use remote control equipment.’
    • ‘Operated by the Royal Observer Corps, it was also charged with monitoring lethal radioactive fallout.’
    • ‘On average, how much time will pass before a radioactive atom decays?’