Definition of half–life
1 : the time required for half of something to undergo a process: such asa : the time required for half of the atoms of a radioactive substance to become disintegratedb : 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
2 : a period of usefulness or popularity preceding decline or obsolescence slang usually has a short half–life
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First Known Use of half–life
1907
HALF–LIFE Defined for English Language Learners
half-life
playDefinition of half–life for English Language Learners
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: the time it takes for a radioactive substance to lose half its radioactivity
HALF–LIFE Defined for Kids
half–life
playDefinition of half–life for Students
half–lives
\-ˌlīvz\: the time required for half of the atoms of a radioactive substance to change composition
Medical Dictionary
half–life
playMedical Definition of half–life
: the time required for half of something to undergo a process: asa: the time required for half of the atoms of a radioactive substance to become disintegratedb: the time required for half the amount of a substance (as a drug or radioactive tracer) in or introduced into a living system or ecosystem to be eliminated or disintegrated by natural processes the serum half–life is about 2 days—Journal of the American Medical Association
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See words that rhyme with half–life Spanish Central: Translation of half–life
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