Children's, Intermediate and Advanced Online English Dictionary & Thesaurus

Comprehensive
Dictionary Suite
Help
Help
Help
 
   
Display options
Show syllables
Show Lookup History
Double-Click Lookup
  Show Spanish support
 
Pronunciation
Wordsmyth
  Phonics
  IPA
 
Entry formats
Standard
  Classic
 
Lookup History
radioactivity

ra·di·o·ac·tiv·i·ty

radioactivity

pronunciation:
reI di o aek tI vih ti
features:
Word Explorer
part of speech: noun
definition: the emission or amount of emission of energy or subatomic particles by the nuclei of certain unstable isotopes of elements as they decay.
Word Explorer
See
  measurement