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 The root in your photo has been repeatedly exposed to moisture and decay because a mower has cut into it time and again. Neil Sperry, ExpressNews.com, "Neil Sperry: Sawfly damage to bur oak leaves is mostly cosmetic," 4 June 2020 Four physicists realized in 2006 that if extremal black holes can decay, this implies that gravity must be the weakest force in any possible universe, a powerful statement about quantum gravity’s relationship to the other quantum forces. Quanta Magazine, "Black Hole Paradoxes Reveal a Fundamental Link Between Energy and Order," 28 May 2020 Heavier quarks decay into their lighter variations, almost always switching their charge, too. Quanta Magazine, "Growing Anomalies at the Large Hadron Collider Raise Hopes," 26 May 2020 Abdel-Wahab found her district transformed into a decrepit sprawl of densely populated, illegally built concrete towers stretching for miles, the sewage systems decaying, the canals paved over or choked with garbage. Washington Post, "Lives Lost: Generous Egyptian grandma was family ‘jewel’," 6 May 2020 Permafrost won’t decay because of warm temperatures alone. Madeline Ostrander, Smithsonian Magazine, "In a Tunnel Beneath Alaska, Scientists Race to Understand Disappearing Permafrost," 4 May 2020 Here, McCoy realized a parallel with the oil business: The amount of oil produced by a given oil well also decays at a decelerating rate over time. Jon Hartley, National Review, "Trading Down with First-Round Picks Is a Path to NFL-Title Contention," 23 Apr. 2020 Carbon-14 decays at a steady rate, meaning the radioisotope is a useful tool for estimating ages of objects. Jennifer Leman, Popular Mechanics, "Could Atomic Weapons from the Cold War Save the World's Largest Fish?," 6 Apr. 2020 Then the deer vanished, the docks decayed, the towers fell. Campbell Mcgrath, The New Yorker, "At the Ruins of Yankee Stadium," 20 Apr. 2020 Recent Examples on the Web: Noun Over time, heat from the radioactive decay of elements in the dwarf planet’s core would have enabled a liquid ocean to form below the surface ice. Popular Science, "Frigid Pluto may have had a toasty start," 29 June 2020 The radioactive decay of potassium-40 is one kind of geological clock. Eliot Bush, Scientific American, "The Meaning of Time in the Place where Humanity's Earliest Ancestors Arose," 27 June 2020 Check the bottom of the container for dampness or stains, which indicate decay. Darlene Zimmerman, Detroit Free Press, "Top pancakes with strawberry and rhubarb sauce loaded with vitamin C," 26 June 2020 Europa’s ocean may have formed after water-rich minerals ejected their water thanks to heating caused by the decay of radioactive elements in its interior early in its history, the researchers found. NBC News, "Subsurface ocean on Jupiter's moon Europa was potentially 'habitable,' researchers say," 25 June 2020 The process of decay, Dunbar explains, has essentially been sped up because of it. Zoe Beaty, refinery29.com, "Is Lockdown Making Our Friendships Decay?," 22 June 2020 One 2017 study found that honey and cinnamon appear to work together to fight against Streptococcus mutans, a bacterium known for its role in tooth decay. Miriam Fauzia, USA TODAY, "Fact check: A mix of honey and cinnamon may have some health benefits, more studies needed," 15 June 2020 And if your knees creak from past injury or arthritis, try another exercise; running could worsen joint decay. Gretchen Reynolds, Health.com, "How Much Exercise Do You Need, and Which Type is Best for You?," 11 June 2020 But space is a different environment and some early evidence suggests the rate of decay is faster off-planet. Troy Farah, Ars Technica, "Vicodin, ketamine, and caffeine: The ingredients of a good space pharmacy," 8 June 2020

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

24 Jun 2020

Cite this Entry

“Decay.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/decay. Accessed 8 Jul. 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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