English

Definition of half-life noun from the Oxford Advanced Learner's Dictionary

     

    half-life

     noun
    noun
    BrE
     
    ; NAmE
     
    [countable]
     
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  1. 1(physics) the time taken for the radioactivity of a substance to fall to half its original value
  2. 2the time taken for the concentration of a substance in the body to fall to half its original value
See the Oxford Advanced American Dictionary entry: half-life