decay

verb
de·​cay | \ di-ˈkā How to pronounce decay (audio) \
decayed; decaying; decays

Definition of decay

 (Entry 1 of 2)

intransitive verb

1 : to undergo decomposition decaying fruit Her teeth were decaying. … most isotopes of copper decay quickly, but two are stable: Cu-63 and Cu-65.— David E. Thomas
2 : to decline in health, strength, or vigor Her mind is beginning to decay with age. believes that the moral fiber of our society is decaying
3 : to fall into ruin the city's decaying neighborhoods
4 : to decline from a sound or prosperous condition a decaying empire
5 : to decrease usually gradually in size, quantity, activity, or force The three voices … decayed and died out upon her ear.— Thomas Hardy

transitive verb

1 : to destroy by decomposition wood decayed by bacteria
2 obsolete : to cause to decay : impair Infirmity, that decays the wise …— William Shakespeare

decay

noun

Definition of decay (Entry 2 of 2)

1a : rot The material is … resistant to fire, decay and termites …— Jack McClintock specifically : aerobic decomposition of proteins chiefly by bacteria
b : the product of decay tooth decay
2 : gradual decline in strength, soundness, or prosperity or in degree of excellence or perfection the decay of the public school system
3 : a decline in health or vigor mental decay
4 : a wasting or wearing away : ruin a neighborhood that had fallen into decay
5 : decrease in quantity, activity, or force: such as
a chemistry : spontaneous decrease in the number of radioactive atoms in radioactive material
b physics : spontaneous disintegration (as of an atom or a particle)
6 obsolete : destruction, death … sullen presage of your own decay.— Shakespeare

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Other Words from decay

Verb

decayer noun

Choose the Right Synonym for decay

Verb

decay, decompose, rot, putrefy, spoil mean to undergo destructive dissolution. decay implies a slow change from a state of soundness or perfection. a decaying mansion decompose stresses a breaking down by chemical change and when applied to organic matter a corruption. the strong odor of decomposing vegetation rot is a close synonym of decompose and often connotes foulness. fruit was left to rot in warehouses putrefy implies the rotting of animal matter and offensiveness to sight and smell. corpses putrefying on the battlefield spoil applies chiefly to the decomposition of foods. keep the ham from spoiling

Examples of decay in a Sentence

Verb the smell of decaying rubbish dead plants and leaves decayed by bacteria She believes that the moral fiber of our society is decaying. our decaying public school system The city's neighborhoods are decaying. Noun the decay of dead plants and leaves She writes about the moral decay of our society. the patient's physical and mental decay The city's neighborhoods are in slow decay.
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Recent Examples on the Web: Verb By choosing the energy of the protons correctly, Beryllium in a particular excited state is produced, which quickly decays back to its ground state by emitting an electron and a positron. Chris Lee, Ars Technica, "New boson appears in nuclear decay, breaks standard model," 20 Dec. 2019 From government initiatives to citizen science projects, thousands of people are working to recover and digitize these rapidly decaying records so they can be incorporated into existing data sets. Washington Post, "How we know global warming is real," 19 Dec. 2019 This quality can help impede bacterial growth and decay around these samples as well. Caroline Delbert, Popular Mechanics, "This 5,700-Year-Old Chewing Gum Contains a Complete Human Genome," 19 Dec. 2019 Set in the freezing Thanksgiving mean streets of Detroit, there are glimpses of landmarks (hello, pre-Ford decaying Michigan Central Station!). Julie Hinds, Freep.com, "These are the 50 most essential movies set in Michigan," 12 Dec. 2019 Some coffins containing adult burials may also have decayed underground and some remains may have been moved to another cemetery. Fox News, "Graves of 145 people found in lost cemetery under Florida high school," 22 Nov. 2019 Far from being an overrun bucket-list checkoff site, Alcatraz in the late 1960s was a deserted, decaying shell. Steve Rubenstein, SFChronicle.com, "50 years later, Native Americans return to Alcatraz to remember occupation," 20 Nov. 2019 Different materials break down at different rates, and small things decay faster than large chunks. Beth Botts, chicagotribune.com, "Your free composting starter kit is falling from the trees right now," 2 Oct. 2019 Over time, the bells—and the whale horns—will decay and disappear, but both projects are gloriously captured for posterity on film. The Economist, "Christian Boltanski’s search for life after death," 17 Dec. 2019 Recent Examples on the Web: Noun But with cats, so brief is their span, every sign of vigor invariably comes with a foreshadowing of decay. V. S. Naipaul, The New Yorker, "The Strangeness of Grief," 30 Dec. 2019 Their estimates reportedly relied on measures of radioactive uranium decay in bones, and of tooth enamel damage from natural radioactivity in the soil and from cosmic rays. Fox News, "Homo erectus’ last known appearance dates to about 117,000 years ago, study reveals," 19 Dec. 2019 This symmetry would be all well and good if physicists had not discovered in 1964 that the weak nuclear force doesn’t share it: Two-quark particles called neutral kaons decay in ways CP symmetry forbids. Quanta Magazine, "Top Dark Matter Candidate Loses Ground to Tiniest Competitor," 27 Nov. 2019 Back in July, Fox News' Tucker Carlson raised the issue of homelessness and urban decay in an interview with Trump. Philip Bump, chicagotribune.com, "Trump reveals motivation for his anti-homelessness push: foreign real estate tenants," 18 Sep. 2019 This particular tomography was developed for use by arborists to detect decay in urban and suburban trees, mainly for safety purposes. Jan Ellen Spiegel, Quartz, "Scientists are finding that forests aren’t as good at fighting climate change as we thought," 12 Sep. 2019 Detectives also found signs of decay in his car and blood evidence in his apartment. Faith Karimi, CNN, "Suspect in Maleah Davis' death says 'nothing bad happened' as mom demands answers," 5 June 2019 If the anode was coated with negative charges, the scientists realized, those layers repel chloride and temper the rate of decay in the underlying metal. David Grossman, Popular Mechanics, "Scientists Are Now Transforming Saltwater Into Hydrogen Fuel," 20 Mar. 2019 And the more functioning, defunct or fragmented objects up there, the more that decay in the atmosphere (pink stripe). Mark Fischetti, Scientific American, "Relentless Rise of Space Junk Threatens Satellites and Earth," 1 Feb. 2019

These example sentences are selected automatically from various online news sources to reflect current usage of the word 'decay.' Views expressed in the examples do not represent the opinion of Merriam-Webster or its editors. Send us feedback.

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First Known Use of decay

Verb

15th century, in the meaning defined at intransitive sense 4

Noun

15th century, in the meaning defined at sense 2

History and Etymology for decay

Verb and Noun

Middle English, from Anglo-French decaïr, from Late Latin decadere to fall, sink, from Latin de- + cadere to fall — more at chance

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Time Traveler for decay

Time Traveler

The first known use of decay was in the 15th century

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Statistics for decay

Last Updated

8 Jan 2020

Cite this Entry

“Decay.” The Merriam-Webster.com Dictionary, Merriam-Webster Inc., https://www.merriam-webster.com/dictionary/decay. Accessed 21 January 2020.

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More Definitions for decay

decay

verb
How to pronounce decay (audio)

English Language Learners Definition of decay

 (Entry 1 of 2)

: to be slowly destroyed by natural processes : to be slowly broken down by the natural processes that destroy a dead plant or body
: to slowly lose strength, health, etc.
of a building, area, etc. : to go slowly from a bad condition to a worse condition : to slowly enter a state of ruin

decay

noun

English Language Learners Definition of decay (Entry 2 of 2)

: the process or result of being slowly destroyed by natural processes
: the slow loss of strength, health, etc.
of a building, area, etc. : the process or result of going slowly from a bad condition to a worse condition

decay

verb
de·​cay | \ di-ˈkā How to pronounce decay (audio) \
decayed; decaying

Kids Definition of decay

 (Entry 1 of 2)

1 : to break down or cause to break down slowly by natural processes Fruit decayed on the ground. Sugar decays teeth.
2 : to slowly worsen in condition The old theater decayed.

decay

noun

Kids Definition of decay (Entry 2 of 2)

1 : the process or result of slowly breaking down by natural processes The schoolhouse being deserted soon fell to decay— Washington Irving, “Sleepy Hollow”
2 : a gradual worsening in condition a decay in manners
3 : a natural change of a radioactive element into another form of the same element or into a different element
de·​cay | \ di-ˈkā How to pronounce decay (audio) \

Medical Definition of decay

 (Entry 1 of 2)

: to undergo decomposition

transitive verb

: to destroy by decomposition

decay

noun

Medical Definition of decay (Entry 2 of 2)

1a : rot sense 1 specifically : aerobic decomposition of proteins chiefly by bacteria
b : the product of decay
2a : spontaneous decrease in the number of radioactive atoms in radioactive material
b : spontaneous disintegration (as of an atom or a nuclear particle)

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More from Merriam-Webster on decay

Thesaurus: All synonyms and antonyms for decay

Rhyming Dictionary: Words that rhyme with decay

Spanish Central: Translation of decay

Nglish: Translation of decay for Spanish Speakers

Britannica English: Translation of decay for Arabic Speakers

Britannica.com: Encyclopedia article about decay

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