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

Keep scrolling for more

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.
See More
Recent Examples on the Web: Verb In the end, Emily decided to forgo embalming and have her body kept on ice for a home vigil before being placed in the ground to decay. Star Tribune, "When cancer hijacked a new mother's happily ever after, she planned a death as unconventional as her life. A year later, her husband is the father he never expected to be, carrying on her legacy.," 11 Oct. 2020 Their faces begin to decay and their eyes are swallowed up. Shannon Carlin, refinery29.com, "The Haunting of Bly Manor," 9 Oct. 2020 However, most mulch products are made from wood byproducts, and dead wood will always eventually decay in the presence of moisture. Beth Botts, chicagotribune.com, "Landscape fabric can do more harm than good under mulch in your garden. Here’s a better, cheaper alternative to try.," 26 Sep. 2020 These fungi decay organic debris in the lawn — grass clippings and dead leaves would otherwise accumulate and choke out the grass. Dan Gill, NOLA.com, "Dan Gill's mailbag: Get rid of dallisgrass while it's young, but mushrooms aren't so bad," 23 Sep. 2020 For example, if an option’s theta is minus 0.20, an investor can expect its premium to decline, or decay, 20 cents a day, if everything else remains constant. Nick Ravo, WSJ, "These Options Terms Are Greek to You," 5 Oct. 2020 And, as in the other study, the protein took longer to decay in human cells. John Timmer, Ars Technica, "When building an embryo, timing is everything," 19 Sep. 2020 Salvors like Pritchett protest that archaeologists are willing to let ships decay in the dark deeps. Chad Lewis, Smithsonian Magazine, "A Shipwreck Off Florida’s Coast Pits Archaeologists Against Treasure Hunters," 22 Jan. 2020 The law illuminates how these fundamental phenomena form, interact, evolve and decay. Quanta Magazine, "An Unexpected Twist Lights Up the Secrets of Turbulence," 3 Sep. 2020 Recent Examples on the Web: Noun The Versailles project quickly began to show signs of decay. Tim Blanning, WSJ, "‘King of the World’ Review: Solar Power," 16 Oct. 2020 They are typically predicted to be 1–1,000 times heavier than protons and to interact with matter only feebly — through the weak nuclear force, which is responsible for radioactive decay, or something even weaker. Elizabeth Gibney, Scientific American, "Last Chance for WIMPs: Physicists Launch All-Out Hunt for Dark-Matter Candidate," 8 Oct. 2020 Friendship decay is hardly unusual; people roll in and out of our lives continuously and cyclically. Zoe Beaty, refinery29.com, "Is Lockdown Making Our Friendships Decay?," 22 June 2020 For more than a decade, Willson has struggled to save the vessel, first from the scrapyard, then from prowlers and county regulators, and, almost always from its own slow decay. Kurtis Alexander, San Francisco Chronicle, "Shipwrecked on Little Potato Slough," 8 Oct. 2020 Originally decorated with murals in 2015 and dedicated in 2016, the paint on the 2,500-square foot concrete underpass was in a state of decay, so Vernon Greenways volunteers determined the time was right for a do-over. Steve Smith, courant.com, "Rails-to-trails underpass gets new mural," 7 Oct. 2020 The rate of decay tends to accelerate as the option nears expiration. Nick Ravo, WSJ, "These Options Terms Are Greek to You," 5 Oct. 2020 That decay is actually one of the great benefits of mulch. Beth Botts, chicagotribune.com, "Landscape fabric can do more harm than good under mulch in your garden. Here’s a better, cheaper alternative to try.," 26 Sep. 2020 Democratic decay is less advanced in the United States. John O'sullivan, National Review, "Conventions in a Time of Revolution," 27 Aug. 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.

See More

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

Keep scrolling for more

Learn More about decay

Time Traveler for decay

Time Traveler

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

See more words from the same century

Statistics for decay

Last Updated

22 Oct 2020

Cite this Entry

“Decay.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/decay. Accessed 27 Oct. 2020.

Keep scrolling for more

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)

Keep scrolling for more

Comments on decay

What made you want to look up decay? Please tell us where you read or heard it (including the quote, if possible).

WORD OF THE DAY

Test Your Vocabulary

Namesakes Word Quiz

  • a citrus fruit possibly named after a person
  • Which of the following is a fruit named after a Moroccan seaport?
Spell It

Can you spell these 10 commonly misspelled words?

TAKE THE QUIZ
Bee Cubed

Test Your Knowledge - and learn some interesting things along the way.

TAKE THE QUIZ
Love words? Need even more definitions?

Subscribe to America's largest dictionary and get thousands more definitions and advanced search—ad free!