From Longman Dictionary of Contemporary Englishradioactivityra‧di‧o‧ac‧tiv‧i‧ty /ˌreɪdiəʊækˈtɪvəti $ -dioʊ-/ noun [uncountable] HCSGPthe sending out of radiation (=a form of energy) when the nucleus (=central part) of an atom has broken apart the discovery of radioactivity high levels of radioactivity
Examples from the Corpus
radioactivity• The first is the internal heat produced by radioactivity in the Earth.• That upsets some anti-nuclear activists, who claim that a rocket explosion could spew cancer-causing radioactivity into the atmosphere.• As the uranium reacts its radioactivity produces unstable atoms.• No radioactivity was detected, and there was no disruption of aircraft electronics.• At St-Aubin, soil contains 30 times the acceptable level of radioactivity.• Workers were exposed to high levels of radioactivity.• The ratio of radioactivity of ulcer area v intact mucosa was calculated for each group of rats.• Strong traces of radioactivity were discovered in the tombs, which is credited with having arrested dissolution.• There, they surrendered cigarettes, breath mints and gum, which might pick up radioactivity that could be ingested. 