Definitions
American Heritage® Dictionary of the English Language, Fourth Edition
- n. Physics The time required for half the nuclei in a sample of a specific isotopic species to undergo radioactive decay.
- n. Biology The time required for half the quantity of a drug or other substance deposited in a living organism to be metabolized or eliminated by normal biological processes. Also called biological half-life.
- n. Biology The time required for the radioactivity of material taken in by a living organism to be reduced to half its initial value by a combination of biological elimination processes and radioactive decay.
Wiktionary
- n. physics The time required for half of the nuclei in a sample of a specific isotope to undergo radioactive decay.
- n. chemistry In a chemical reaction, the time required for the concentration of a reactant to fall from a chosen value to half that value.
- n. medicine The time it takes for a substance (drug, radioactive nuclide, or other) to lose half of its pharmacological, physiologic, or radiological activity.
- n. The time it takes for an idea or a fashion to lose half of its influential power.
GNU Webster's 1913
- n. (Physics) the time it takes for one-half of a substance decaying in a first-order reaction to be destroyed. For radioactive substances, it is the time required for one-half of the initial amount of the radioactive isotope to decay. The
half-life is a measure of the rate of the reaction being observed. For processes that are true first-order processes, such as radioactive decay, thehalf-life is independent of the quantity of material present, and it is thus a constant. The time it takes for one-half the remaining quantity of a radioactive isotope to decay will be the same regardless of how far the decay process has advanced. Some chemical reactions are also first order, and may be characterized as having ahalf-life. However, for chemical reactions thehalf-life will depend upon temperature and in some cases other environmental conditions, whereas for radioactive isotopes the rate of decay is largely independent of the environment.
WordNet 3.0
- n. the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)
- n. the time required for something to fall to half its initial value (in particular, the time for half the atoms in a radioactive substance to disintegrate)
Etymologies
- half- + life (Wiktionary)
Examples
“Everyone metabolizes caffeine at a different a rate, but in general it takes approximately three to seven hours for the body to eliminate half of the total amount of caffeine also called the half-life.”
“One of the properties that govern isotopes is a phenomenon called half-life.”
“But on closer inspection, I discovered that many were also struggling with what I now call the half-life of eating disorders.”
“With a half-life of 30 years, Cs-137 gives off potentially hazardous external penetrating radiation.”
The Huffington Post: Robert Alvarez: America's Nuclear Spent-Fuel Time Bombs
“The cesium, with a half-life of 30 years, is likely the main long-term health threat from Fukushima, although prevailing winds during the March accident blew most of it out to sea.”
The Wall Street Journal: Past Haunts Tally of Japan's Nuke Crisis
“Three different types of cesium were discovered, one of which has a half-life of 30 years.”
“One sample of konago caught Friday contained twice the permissible level of radioactive iodine-131, which has a half-life of eight days and which can accumulate in the thyroid in humans, possibly raising the risk of thyroid cancer.”
“You can abandon a half-life of self-pity and embrace a life filled with purpose and enhanced character development.”
“By looking to God for the future rather than blaming Him for the past, I chose life over the debilitating half-life of bitterness.”
“It will have a half-life of half a month, then die very slowly.”
Lists
These user-created lists contain the word ‘half-life’.
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Interesting words
A list of words that are odd or words that I have looked up.
concupiscence, brize, scree, scoria, forestaff, spanaemia, valetudinarianism, distasture, pyrethrum, laudanum, gentian, bicameral and 11250 more...
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Life is rife .................
-ife- & -iferous : common and not-so-common words about life
fructiferous, ifere, glomuliferous, graniferous, guttiferales, lifen, manifest, nimbiferous, oviferous, roriferous, petaliferous, rangifer and 105 more...
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hyphenated halfs
are a lot of these halfs half-thought-out?
half-cocked, half-breed, half-bath, half-assed, half-a-buck, half-baked, half-dead, half-asleep, half-back, half-clothed, half-done, half-dozen and 74 more...
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by half
half as good as most lists
halfheimers, half time, halfhearted, half a mind to, half nelson, half caf, half and half, half-pint, half-cocked, half-wit, half again, half-crazed and 19 more...
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Pure science
good words related to math, physics, logic and other fields that I don't know enough of, but like anyway...
Sisyphus cooling, forbidden mechanism, false vacuum, universal extra d..., strange antiquark, strangelet, nowhere-different..., vacuous truth, deviant logic, exceptional object, monstrous moonshine, forgetful functor and 659 more...
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A Matter Of Time
Favorite time-related words.
vespertine, twilight, gloaming, eftsoon, eventide, dawn, eos, dusk, witching hour, ephemeral, candlemark, autumnal and 122 more...
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thegirlnextfloor's list
autumnal, avalanche, silhouette, antique, abysmal, scorch, sonic, surge, symmetry, whisper, penchant, dissipate and 349 more...
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stevebrullecheckitout
diurnal, furlough, half-life, hourglass, hazard, chintz, palaver, sylvan, staid, curt, winsome, adroit and 52 more...
Tweets
Looking for tweets for half-life.
zaggan if i'm right this is a game title. my aunt plays it all the time it is kind of cool. May 27, 2009