Definition of radioactive in English:
 radioactive
adjective ˌreɪdɪəʊˈaktɪvˌreɪdioʊˈæktɪv
Emitting or relating to the emission of ionizing radiation or particles.
 the water was radioactive
 Example sentencesExamples
-  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.
 -  Operated by the Royal Observer Corps, it was also charged with monitoring lethal radioactive fallout.
 -  They fill up the thyroid gland and stop it from absorbing any radioactive iodine released by the reactor.
 -  He explained spent nuclear fuel is not radioactive waste because it can be reused.
 -  On average, how much time will pass before a radioactive atom decays?
 -  The C-urea breath test detects current infection and is not radioactive.
 -  This three-year project was to lead to the discovery of the causes of radioactive emissions.
 -  The specific activity of the radioactive thiamine was the same for each concentration used.
 -  They realized that the particles emitted by radioactive elements as they decay are in fact little bits of the atomic nuclei.
 -  In reality all they did was make my blood radioactive before taking gamma photographs.
 -  It is so hot and radioactive that the miners use remote control equipment.
 -  Nuclear fusion produces no greenhouse gas emissions and only low levels of radioactive waste.
 -  Radon decays to form tiny radioactive particles, some of which remain suspended in the air.
 -  Part of the problem is that as the radioactive substance decays, most of the electrons miss the silicon surface.
 -  They also debated earnestly over how polluted and radioactive they thought the Caspian's waters were.
 -  Depleted uranium is a radioactive heavy metal, which is also chemically toxic.
 -  The periodic table has since been expanded to 81 stable and 31 radioactive elements.
 -  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.
 
Derivatives
  
adverb 
 Uranium decays radioactively to produce thorium - 230 at a known rate.
 Example sentencesExamples
-  Specimens of fish and amphibians taken from radioactively contaminated or otherwise polluted areas also show some apparent fluctuations in DNA content.
 -  It is unstable, and scientists know that it radioactively decays by electron emission to Nitrogen 14, with a half life of 5730 years.
 -  ‘There is likely to be an increase in radioactively contaminated metals and other radioactive sources entering the scrap supply chain,’ he said.
 -  Those four iron isotopes are all radioactively stable.
 
   Definition of radioactive in US English:
 radioactive
adjectiveˌrādēōˈaktivˌreɪdioʊˈæktɪv
Emitting or relating to the emission of ionizing radiation or particles.
 the water was radioactive
 Example sentencesExamples
-  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?