half-life

See also: halflife

English

Etymology

From half- +‎ life.

Pronunciation

• (US) IPA^(key): /ˈhæfˌlaɪf/

• Audio (US):

  (file)

Noun

half-life (plural half-lives)

1. (physics) The time required for half the nuclei in a sample of an isotope to undergo radioactive decay.
2. (chemistry) In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
3. (medicine) The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
4. The time it takes for an idea or a fashion to lose half of its influential power.
   • 1991, Robert Ackerman, Introduction to Jane Ellen Harrison's Prolegomena to the Study of Greek Religion (1903)

     Most books of scholarship have surprisingly short intellectual 'half-lives during which they make a difference"

Translations

time in physics

• Afrikaans: ^{(please verify)} halfleeftyd
• Armenian: կիսատրոհման պարբերություն (hy) (kisatrohman parberutʻyun)
• Azerbaijani: yarımdağılma dövrü
• Belarusian: перыяд паўраспаду n (pjeryjad paŭraspadu)
• Bulgarian: период на полуразпад m (period na polurazpad)
• Catalan: període de semidesintegració m, període radioactiu m
• Chinese:

  Mandarin: 半衰期 (zh) (bànshuāiqī)

• Czech: poločas rozpadu m
• Danish: halveringstid (da) c
• Dutch: halfwaardetijd (nl) m, halveringstijd (nl) m
• Esperanto: duoniĝa tempo
• Estonian: poolestusaeg (et)
• Finnish: puoliintumisaika (fi)
• French: demi-vie (fr) f
• Galician: período de semidesintegración m
• Georgian: ნახევარდაშლის პერიოდი (naxevardašlis ṗeriodi), ნახევრად დაშლის პერიოდი (naxevrad dašlis ṗeriodi)
• German: Halbwertszeit (de) f
• Greek: χρόνος ημιζωής m (chrónos imizoḯs)
• Hebrew: ^{(please verify)} מחצית חיים
• Hindi: अर्धायु (ardhāyu)
• Hungarian: felezési idő (hu)
• Icelandic: helmingunartími
• Indonesian: waktu paruh
• Irish: leathré (ga) f
• Italian: emivita (it) f, semivita f
• Japanese: 半減期 (はんげんき, hangenki)
• Kannada: ಅರ್ಧಾಯುಷ್ಯ (ardhāyuṣya)
• Kazakh: жартылай ыдырау мерзімі (jartylai ydyrau merzımı)
• Korean: 반감기 (ko) (ban'gamgi)
• Latvian: pussabrukšanas periods
• Lithuanian: pusėjimo trukmė
• Macedonian: период на полураспад m (period na poluraspad)
• Malay: separuh hayat
• Malayalam: അർദ്ധായുസ്സ് (aṟddhāyussŭ)
• Norwegian:

  Bokmål: halveringstid (no) m or f

  Nynorsk: halveringstid f

• Persian: نیمه‌عمر (nime-'omr)
• Polish: czas połowicznego rozpadu m, okres połowicznego rozpadu m
• Portuguese: meia-vida f, semivida f
• Romanian: perioadă de înjumătățire (ro) f
• Russian: пери́од полураспа́да (ru) m (períod poluraspáda)
• Serbo-Croatian:

  Roman: vreme poluraspada n

• Slovak: polčas premeny m
• Slovene: razpolovni čas m
• Spanish: periodo de semidesintegración m; semivida f, vida media f
• Swedish: halveringstid (sv) c
• Tagalog: kalahatimbuhay
• Tamil: அரைவாழ்வுக் காலம் (araivāḻvuk kālam)
• Telugu: అర్థ జీవితకాలం (artha jīvitakālaṁ)
• Thai: ครึ่งชีวิต
• Turkish: ^{(please verify)} yarılanma süresi
• Ukrainian: пері́од напівро́зпаду m (períod napivrózpadu)
• Urdu: ^{(please verify)} ہاف لائف
• Uzbek: yarim yemirilish davri
• Vietnamese: chu kì bán rã, chu kỳ bán rã, chu kỳ nửa phân rã

chemistry: time required for concentration to fall to half

• Catalan: semivida f
• Finnish: puoliintumisaika (fi)
• French: demi-vie (fr) f
• German: Halbwertszeit (de) f
• Hungarian: felezési idő (hu)
• Indonesian: waktu paruh
• Italian: emivita (it) f, semivita f
• Japanese: 半減期 (はんげんき, hangenki)
• Malay: separuh hayat
• Russian: пери́од полужи́зни m (períod polužízni)
• Spanish: semivida
• Tagalog: kalahatimbuhay

medicine: time for a substance to lose half of its activity

• Catalan: semivida f
• Finnish: puoliintumisaika (fi)
• Indonesian: waktu paruh
• Japanese: 半減期 (はんげんき, hangenki)
• Malay: separuh hayat
• Norwegian:

  Bokmål: halveringstid (no) m or f

  Nynorsk: halveringstid f

• Russian: пери́од полувыведе́ния m (períod poluvyvedénija)

time to lose half of influential power of an idea or fashion

• Finnish: puoliintumisaika (fi)

The translations below need to be checked and inserted above into the appropriate translation tables. See instructions at Wiktionary:Entry layout § Translations.

Translations to be checked

• Arabic: عُمْر النِصْف (ʕumr an-niṣf)
• Esperanto: duoniĝa tempo
• Estonian: poolestusaeg (et)
• Greek: περίοδος ημιζωής m (períodos imizoḯs) (1)
• Hebrew: מחצית חיים
• Icelandic: helmingunartími m (1)
• Italian: tempo di dimezzamento m (1,2,3)
• Portuguese: período de semidesintegração m