half-life en · NOUN
Pronunciation
- (US) audio
- /ˈhæfˌlaɪf/ (US)
Etymology
Etymology tree English half- Proto-Indo-European *leyp- Proto-Germanic *lībanąder. Proto-Germanic *lībą Proto-West Germanic *līb Old English līf Middle English lyf English life English half-life From half- + life.
Meanings
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(qualifier:nuclear physics) The time required for half the nuclei in a sample of an isotope to undergo radioactive decay.
"The guy that just left—what's he got in his lungs?" / "Well, I'm not very sure. But the two best candidates are uranium-233 and plutonium-239, one or both." / "They're in his bones too, aren't they?" / "Yeah, they're both boneseekers. And they've got half-lives of one hundred sixty-two thousand and twenty-four thousand years respectively. So they stay hot for a long time."
1985, Michael Swanwick, “Boneseeker”, in In the Drift (New Ace Science Fiction Specials; series 3), New York, N.Y.: Ace Science Fiction Books, →ISBN; republished New York, N.Y.: Dover Publications, 2017, →ISBN, page 80:O₂^(•−) and OH^• are highly unstable (half-life at the level of microseconds and nanoseconds, respectively) and cannot cross membrane, while H₂O₂, though not a free radical but a ROS, is relatively stable (half-life around 1 ms) (Møller et al. 2007) and can cross membranes through aquaporins.
2015, Rup Kumar Kar, “ROS Signaling: Relevance with Site of Production and Metabolism of ROS”, in Dharmendra K. Gupta, José M. Palma, Francisco J. Corpas, editors, Reactive Oxygen Species and Oxidative Damage in Plants Under Stress, Springer, →ISBN, page 117:
- (physical) In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
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The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
For nonporous surfaces such as steel, in a dark and low-humidity environment, the CCP virus has an 18-hour half-life—the time required for it to decrease by half , according to the researchers' findings.
2020, Dr. Alan Pateman, China, Covid-19, World Domination, Lulu Press, Inc, →ISBN:
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The amount of time it takes for an idea or a fashion to lose half of its influential power.
Most books of scholarship have surprisingly short intellectual half-lives during which they make a difference"
1991, Robert Ackerman, Introduction to Jane Ellen Harrison's Prolegomena to the Study of Greek Religion (1903)
Forms
| Spelling | Features | Labels | Source |
|---|---|---|---|
| half-lives | Number=Plur | lexicographic |
Relateds
Translations (83)
el χρόνος ημιζωής (time in physics) · it emivita (time in physics) · nn halveringstid (time in physics) · tl kalahatimbuhay (chemistry: time required for concentration to fall to half) · fi puoliintumisaika (medicine: time for a substance to lose half of its activity) · ms separuh hayat (time in physics) · ca semivida (medicine: time for a substance to lose half of its activity) · cs poločas rozpadu (time in physics) · sk polčas premeny (time in physics) · fr demi-vie (chemistry: time required for concentration to fall to half) · it semivita (time in physics) · ca període radioactiu (time in physics) · sl razpolovni čas (time in physics) · fi puoliintumisaika (time to lose half of influential power of an idea or fashion) · vi chu kì bán rã (time in physics) · ro perioadă de înjumătățire (time in physics) · ca semivida (chemistry: time required for concentration to fall to half) · ta அரைவாழ்வுக் காலம் (time in physics) · ms separuh hayat (medicine: time for a substance to lose half of its activity) · ml അർദ്ധായുസ്സ് (time in physics) · ru пери́од полужи́зни (chemistry: time required for concentration to fall to half) · pl okres połowicznego rozpadu (time in physics) · es semivida (chemistry: time required for concentration to fall to half) · pt meia-vida (time in physics) · be перыяд паўраспаду (time in physics) · nb halveringstid (medicine: time for a substance to lose half of its activity) · cmn 半衰期 (time in physics) · mk период на полураспад (time in physics) · vi chu kỳ bán rã (time in physics) · hi अर्धायु (time in physics) · uk пері́од напівро́зпаду (time in physics) · es vida media (time in physics) · th ครึ่งชีวิต (time in physics) · fi puoliintumisaika (time in physics) · ga leathré (time in physics) · lv pussabrukšanas periods (time in physics) · sh vreme poluraspada (time in physics) · pt semivida (time in physics) · nb halveringstid (time in physics) · te అర్థ జీవితకాలం (time in physics) · hu felezési idő (time in physics) · fa نیمهعمر (time in physics) · pl czas połowicznego rozpadu (time in physics) · fi puoliintumisaika (chemistry: time required for concentration to fall to half) · nl halfwaardetijd (time in physics) · de Halbwertszeit (chemistry: time required for concentration to fall to half) · da halveringstid (time in physics) · ja 半減期 (medicine: time for a substance to lose half of its activity) · nl halveringstijd (time in physics) · ru пери́од полураспа́да (time in physics) · uz yarim yemirilish davri (time in physics) · es semivida (time in physics) · ms separuh hayat (chemistry: time required for concentration to fall to half) · kk жартылай ыдырау мерзімі (time in physics) · hy կիսատրոհման պարբերություն (time in physics) · id waktu paruh (medicine: time for a substance to lose half of its activity) · id waktu paruh (time in physics) · ja 半減期 (time in physics) · bg период на полуразпад (time in physics) · hu felezési idő (chemistry: time required for concentration to fall to half) · is helmingunartími (time in physics) · lt pusėjimo trukmė (time in physics) · az yarımdağılma dövrü (time in physics) · ca període de semidesintegració (time in physics) · gl período de semidesintegración (time in physics) · eo duoniĝa tempo (time in physics) · ja 半減期 (chemistry: time required for concentration to fall to half) · sv halveringstid (time in physics) · ka ნახევრად დაშლის პერიოდი (time in physics) · id waktu paruh (chemistry: time required for concentration to fall to half) · tl kalahatimbuhay (time in physics) · et poolestusaeg (time in physics) · de Halbwertszeit (time in physics) · it semivita (chemistry: time required for concentration to fall to half) · ko 반감기 (time in physics) · fr demi-vie (time in physics) · kn ಅರ್ಧಾಯುಷ್ಯ (time in physics) · ka ნახევარდაშლის პერიოდი (time in physics) · vi chu kỳ nửa phân rã (time in physics) · es periodo de semidesintegración (time in physics) · nn halveringstid (medicine: time for a substance to lose half of its activity) · ru пери́од полувыведе́ния (medicine: time for a substance to lose half of its activity) · it emivita (chemistry: time required for concentration to fall to half)