half-life

See also: halflife

English

Etymology

half- +‎ life

Pronunciation

(US) IPA^(key): /ˈhæfˌlaɪf/

Noun

half-life (plural half-lives)

(physics) The time required for half the nuclei in a sample of a specific isotope to undergo radioactive decay.
(chemistry) In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
(medicine) The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
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 parberutʿyun)
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
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 काल (ardhāyu kāl)
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 (ʿumr an-niṣf)
Esperanto: duoniĝa tempo
Estonian: poolestusaeg
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