half-life

noun
half-life \ ˈhaf-ˌlīf \ ˈhäf- \
1907{ds||1||}
  • the time required for half of something to undergo a process: such as
  • the time required for half of the atoms of a radioactive substance to become disintegrated
  • the time required for half the amount of a substance (such as a drug, radioactive tracer, or pesticide) in or introduced into a living system or ecosystem to be eliminated or disintegrated by natural processes
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