Definition of decay in English:



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  • 1(of organic matter) rot or decompose through the action of bacteria and fungi.

    ‘the body had begun to decay’
    • ‘A piece of fruit will decay far less quickly if refrigerated, than if left out in the sun.’
    • ‘Masses of leaves may begin to decay and smother the plant beneath them.’
    • ‘When crown tissue is infected and becomes decayed, the entire plant may wilt and die.’
    • ‘‘Dead and decaying trees and branches are crucial to a vast range of wildlife, from birds to insects and fungi,’ he said.’
    • ‘Organic material decays rapidly, especially in hot climes like that of Egypt, Evershed said.’
    • ‘Apparently all the melted snow water had drenched the wooden beams supporting the mines, causing them to decay and fall apart, taking the ceilings with them.’
    • ‘Organic matter turns dark as it decays and so the higher the organic content of a soil, the darker its colour.’
    • ‘Litter in years gone by was really non existent and not the problem it is today, as packaging was simple and brown paper bags being organic quickly decayed.’
    • ‘They also detected organic chemicals similar to those found when bacteria decay.’
    • ‘Several hundred million years ago, conditions of burial were such that organisms decayed to form products consisting almost entirely of carbon and hydrocarbons.’
    • ‘This is a fungus also caused by excess fish waste and food decaying in the bottom of the tank.’
    • ‘Aspergillus is an ubiquitous fungus found in soil, water, and decaying vegetation.’
    • ‘Considerable nitrogen, phosphorus, and some micronutrients are released from organic matter as it is oxidized or decays.’
    • ‘Billy has been left with only eight back teeth and his two front incisors, which dentists say are so badly decayed they will fall out in months.’
    • ‘The tree was badly decayed and in 1814 it blew down.’
    • ‘It is formed from decomposing underground deposits of organic matter such as decaying plant material.’
    • ‘As vegetation falls to the ground, it slowly decays, providing minerals and nutrients needed for plants, animals and microorganisms.’
    • ‘The rainforests have almost no net effect on the world's oxygen levels, since decaying plant matter in the rainforests uses about as much oxygen as the rainforests produce.’
    • ‘After all, there have been many catastrophes that destroy evidence - fossilization is a rare event because animal flesh and bones decay quickly.’
    • ‘Some vegetables may decay before drying, so start with several in order to ensure that one will dry successfully.’
    decompose, rot, putrefy, go bad, go off, spoil, fester, perish, deteriorate
    decomposed, decomposing, rotten, rotting, putrescent, putrid, bad, off, spoiled, spoilt, perished
    decomposing, decomposed, rotting, rotten, putrescent, putrid, bad, off, spoiled, spoilt, perished
    View synonyms
    1. 1.1with object Cause to rot or decompose.
      ‘the fungus will decay soft timber’
      • ‘It is easy for tiny amounts of food to get trapped in the tiny dents or fissures, and if you do not brush them thoroughly, bacteria can build up and start to decay the tooth.’
      • ‘The council said the fungi had decayed the roots.’
      • ‘I stand to inherit a water penetration problem, caused not by my countless tea drinking, but by water decaying the roof beams in the lounge.’
    2. 1.2 Fall into disrepair; deteriorate.
      ‘facilities decay when money is not spent on refurbishment’
      • ‘An excursion out of the capital quickly reveals signs of abject poverty, evident in massive land erosion from over-cropping and the dismal spectacle of abandoned, decaying factories.’
      • ‘A furore over footpaths is brewing in a South Lakeland village after taxpayers learned it could be nearly 10 years before decaying routes are repaired.’
      • ‘From that point, the property has remained uninhabited, and has slowly decayed.’
      • ‘Vancouver's derelict and decayed industrial edifices have often served as a source of inspiration for local artists.’
      • ‘For years Blackburn's Church Street Pavilions have been allowed to crumble and decay so that the Grade ll listed buildings have become nothing more than an eyesore.’
      • ‘Barcelona used its Games in 1992 to implement a wide-ranging urban renewal plan, transforming a decaying industrial city into a sought-after tourist destination.’
      • ‘The new forum needs to make clear that the government understands why so many of them live in the depressed and decaying inner cities and that ministers mean to make a direct assault on the causes of their deprivation.’
      • ‘The castle narrowly failed to win cash from BBC TV's Restoration competition in 2003, leading to fears that the building might decay completely.’
      • ‘The people of Moora have now taken their protest to the Premier directly by gatecrashing all his public appearances and delivering him bricks from their rapidly decaying hospital.’
      • ‘A few suburbs have flourished, while the inner city has decayed and once relatively stable working class communities have deteriorated.’
      • ‘The government hopes that the concession will be awarded before the start of the new tourist season as the decaying state of the two facilities has been the most frequent cause for complaints from foreign tourists lately.’
      • ‘Businessman John Cross wanted to turn the dilapidated and decaying jetty into a shopping mall, bistro-style restaurant and a specialised apartment-style hotel.’
      • ‘On the downside he's noticed that the urban infrastructure has decayed immeasurably in recent years.’
      • ‘The Royal Hall, built as the Kursaal in 1903 to provide entertainment for Edwardian visitors to the spa, faces closure within five years because decaying concrete will make it unsafe.’
      • ‘By registering the buildings as being ‘at risk’, English Heritage is warning the owners that the fabric is decaying.’
      • ‘Once constructed to ensure the safety of Bulgaria's rulers, they remain for the most part unused and neglected, decaying relics of a forgotten era.’
      • ‘In fact, they are slowly decaying Western ghost towns, relics of 19th-century homesteaders and gold seekers who abandoned them decades ago.’
      • ‘Housing association properties in decaying parts of the borough are to receive a £5.3 million overhaul as Bolton Council attempts to stop the rot.’
      • ‘More than 700 decaying homes are to be demolished and rebuilt in a sweeping multi-million regeneration programme.’
      • ‘Century, published by Simon and Schuster is a magical gothic tale about a strange family living in a dark, decaying mansion where it is always dark and eternally winter.’
      deteriorate, degenerate, decline, go downhill, slump, slip, slide, go to rack and ruin, go to seed, run to seed, worsen, crumble, disintegrate, fall to pieces, come apart at the seams, fall into disrepair, become dilapidated
      declining, degenerating, dying, waning, crumbling, collapsing
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    3. 1.3 Decline in quality, power, or vigour.
      ‘the moral authority of the party was decaying’
      • ‘Without the instability of the declining 18th century, as the old European order decayed, we would not have gained the French assistance decisive to our struggle for independence.’
      • ‘He said people were the core of the defence capability today and in the future and if recruiting shortfalls and high loss rates were not addressed then Defence could decay to the point of irrelevance.’
      • ‘Institutional inertia, social customs, and psychological habit ensure that systems can maintain their outer shapes long after they have begun to decay internally.’
      • ‘I think that some people behave in this aggressive and sadly bitter way because they live in a desperate, decaying society.’
      • ‘But inevitably, a society acknowledging no transgenerational commitment to the future will decay and decline from within.’
      • ‘Governmental authority decayed in Poland and Hungary during the early months of 1989.’
      • ‘Democracy under the Republic was decaying to the point at which political assassination was a commonplace.’
      • ‘Her book seems to be about a woman trapped in two decaying relationships, one with her career and the other with her lover.’
      • ‘This is another fine example of the decaying moral standards we are leaving behind for our young ones.’
      • ‘Upon assessing his realm's decaying power, Louis XV allegedly mumbled ‘Après moi, le deluge.’’
      • ‘Now, with reduced capabilities and decayed leadership, they've turned to attacking soft targets.’
      • ‘News of forthcoming private A&E departments demonstrate age-old forces of supply and demand are preparing to work their magic on Britain's flagging and decayed health service.’
    4. 1.4Physics (of a radioactive substance, particle, etc.) undergo change to a different form by emitting radiation.
      ‘the trapped radiocarbon begins to decay at a known rate’
      ‘the W-particle then decays into an electron and a neutrino’
      • ‘The uranium eventually decays to radium and, eventually to polonium - 210, a substance that, when inhaled, can endanger tissue health and damage the immune system.’
      • ‘When uranium decays to lead, a by-product of this process is the formation of helium, a very light, inert gas which readily escapes from rock.’
      • ‘Some atoms can undergo radioactive beta decay, in which a neutron decays into a proton, an electron and an electron-antineutrino via the weak nuclear force.’
      • ‘With radioactive waste, the material will eventually decay to non-radioactive materials, but this process may take thousands of years.’
      • ‘Once solidified, the lead is ‘locked ‘in place and since the uranium decays to lead, the lead-to-uranium ratio increases with time.’’
    5. 1.5technical (of a physical quantity) undergo a gradual decrease.
      ‘the time taken for the current to decay to zero’
      • ‘We found that fluorescence decayed with an averaged time constant of 142.8 s due to photobleaching.’
      • ‘The fluorescence in this pattern decays much slower and is still present 1800 ms after bolus delivery.’
      • ‘Since antibody affinity is expected to stay the same even in AIDS, unlike antibody quantity which decays in advanced disease, this approach is less likely to give false recent classification.’
      • ‘LD decayed relatively slowly but steadily within genes.’
      • ‘Without a power source, this current would decay.’


mass noun
  • 1The state or process of rotting or decomposition.

    ‘hardwood is more resistant to decay than softwood’
    ‘bacterial decay’
    • ‘He was very much aware of the inevitability of decay and death as a part of life, an idea that Dutch artists called ‘Vanitas.’’
    • ‘There's a smell of vegetable decay.’
    • ‘Fluoride is normally added to toothpaste for the treatment of teeth to prevent decay.’
    • ‘When an organism dies, oxidation reactions are responsible for the decay of the organic matter.’
    • ‘The study did not find an association between secondhand smoke exposure and decay in permanent teeth.’
    • ‘Certain of the test compounds have both prevented wood decay and killed native termite colonies.’
    • ‘Chewing gum increases the flow of saliva leading to a reduction in dental decay.’
    • ‘A late complication of neglected dental decay is a dental abscess.’
    • ‘Corn crown and root decay can weaken stalks and complicate harvest.’
    • ‘The report highlights a number of problems, including the degeneration and decay of timber in the upper sections where the tree has been previously topped and pruned.’
    • ‘Children whose teeth fall out early due to decay, may not have straight adult teeth and require a dental brace.’
    • ‘The feedback, clipping, and heavy crackle due to vinyl decay doesn't do much justice as far as preservation goes.’
    • ‘Health authorities tell us that fluoridation is a safe and a highly effective means of preventing dental decay in children.’
    • ‘The rate of product decay is increasing.’
    • ‘Soybean debris in fields with high levels of brown spot infection should be incorporated into the soil with tillage to increase the rate of decay of these plant tissues.’
    • ‘The most common type of tooth damage is decay, caused by a combination of poor toothbrushing and a sugary diet.’
    • ‘Encased in iron or under glass, such relics were especially esteemed for their power to reverse the course of the body's eventual decay by effecting cures or allaying physical pain.’
    • ‘Bald cypress is exotic, and both woods are exceptionally decay resistant and are excellent building materials.’
    • ‘Most fossils are replicas of bones, teeth, shells, and other hard, mineral-based tissues that resist decay.’
    • ‘It is well known that bacterial decay of organic matter in sediment liberates phosphate and bone is also a potential phosphate source.’
    decomposition, rotting, going bad, putrefaction, putrescence, putridity, festering, spoilage, perishing, withering, shrivelling
    rot, rotting, corrosion, corroding, decomposition
    View synonyms
    1. 1.1 Rotten matter or tissue.
      ‘fluoride heals small spots of decay’
      • ‘If you notice black sooty fungus, brown or black spots of decay on leaves or flowers, or broken discoloration on leaves or stems of your orchids, they may be harboring a fungus, bacteria or virus.’
      • ‘When the decay reaches the pulp tissue, the blood vessels, and the nerves that serve the tooth, the pain starts - an insistent throbbing.’
      • ‘Layers of moss and decay give a funereal quality to this weighty hall.’
      • ‘There is a series of different protective proteins that can stop the bacteria adhering and growing and can reduce their ability to produce acid, and these are quite good also at repairing earlier areas of decay.’
      • ‘However, too much growth produces a strain on tissues and early decay.’
    2. 1.2 Structural or physical deterioration.
      ‘the old barn rapidly fell into decay’
      • ‘For all its crumbling decay, the faded splendour, its shortages and its collapsed economy, Cuba is a vibrant and thrilling place to visit.’
      • ‘The early designers of urban-aid programs saw inner-city decay as more than just an economic matter.’
      • ‘‘There is a general feeling around the town that the park is slipping into decay,’ Comm Kiely stated.’
      • ‘Some scientists now believe that smoking may store up liability to stress and cause mental illness as well as physical decay.’
      • ‘Over time, the plant growth not only concealed the structures; it also contributed greatly to their decay.’
      • ‘It comes less than two weeks after the worst blackout in US history, a social disaster that had its roots in the decay of the electrical transmission grid.’
      • ‘Gradually the abandoned buildings fell into decay or were adopted for other uses.’
      • ‘This colossal structure of iron and glass, despite the gradual decay and depletion it suffered over the 82 years of its existence, had not lost its ability to amaze.’
      • ‘Providing new facilities becomes a higher priority than maintaining the same facilities in older neighbourhoods, which also leads to decay in areas near the city centre.’
      • ‘Poor ventilation is a common feature that promotes mold growth and structural decay in buildings.’
      • ‘When it closed the canal was seen as a dirty, decaying relic of an industrial past, and it sank into decay and dereliction.’
      • ‘The home is still empty today, and has suffered considerable interior damage, including structural decay resulting from water leaks in the building.’
      • ‘Due to infrequent maintenance in recent decades, many of the city's grand structures are in terminal decay, undone by the vandalism of official apathy.’
      • ‘One result of increased durability is that obsolescence rather than decay will be the major reason old structures and old products are torn down and thrown away.’
      • ‘A couple of glistening new campuses mask the shocking physical decay of dozens of city schools.’
      • ‘‘Our urban environment is in decay because of a lack of maintenance which is common across Africa,’ Adebayo said.’
      • ‘The home fell into decay by the start of the 1970s.’
      • ‘Smith fears that there are many other paintings in the collection that are in a similar state of decay - what her profession terms ‘actively deteriorating’.’
      • ‘However, in recent times the walkway including the adjacent river has fallen into decay with overgrown weeds, graffiti, dumping.’
      • ‘The health board and the staff looking after these people are doing a wonderful job in a building that is rapidly falling into decay.’
      deterioration, degeneration, debasement, degradation, decline, slipping, waning, ebb, shrinking, withering, weakening, atrophy, crumbling, disintegration, collapse, lapse, fall, failure
      View synonyms
    3. 1.3 The process of declining in quality, power, or vigour.
      ‘the problems of urban decay’
      • ‘For Webster's audience, Italy was perceived as a site of political intrigue, economic power, decadence, and moral decay.’
      • ‘Increased consumption has the potential to increase the number of traffic accidents, increase crime and contribute to the moral decay of the community, she said.’
      • ‘Even some of the great multinationals that were ‘blue chips’ with investors at some point of time have been witnessing gradual decay.’
      • ‘Unlike Britain, Rome succumbed not to the rise of a new empire, but to internal decay and a death of a thousand cuts from various barbarian groups.’
      • ‘It is my conviction that the real reason that the Soviet Union collapsed was not economic ruin or systemic decay: it was cynicism.’
      • ‘A grave economic symptom of decay was… the gradual transference of the entire economy to the ownership of stock companies…’
      • ‘The Supreme Court hearing has underscored the far-reaching decay of bourgeois democracy in the US.’
      • ‘The sense of urban decay is much more evident and the chaos of the street is not balanced but overwhelming.’
      • ‘Traditional societies in underdeveloped countries are no more immune to creeping moral decay than their more sophisticated cousins in rich, developed nations.’
      • ‘In their wake, the giant auto concerns leave behind an industrial wasteland of mass unemployment, ruined infrastructure and social decay.’
      • ‘Every sector of our society seems to be in moral decay.’
      • ‘No politician is talking about ideas or programs to liberate the people from the current economic retrogression and social decay.’
      • ‘It is all part of the decline and decay of our modern culture.’
      • ‘The Soviet Union disintegrated in 1991 after a long period of internal political and economic decline and decay.’
      • ‘People talk a lot about cultural decay and declining values and the blame is usually placed on evil liberals.’
      • ‘Both the attempted coup in Fiji and the ousting of the government in the Solomons have exposed the advanced state of decay in the state structures of these countries.’
      • ‘‘Together let us find solutions to moral decay by jointly developing a strategy and a programme of action,’ Masondo says.’
      • ‘Glass shattered on the pavement, all around are the signs of urban decay.’
      • ‘The goal of conservatism is to defend our civilization from decay and decadence, from a weakening of our principles.’
      • ‘Intellectual deterioration leads to political decay.’
    4. 1.4Physics The change of a radioactive substance, particle, etc. into another by the emission of radiation.
      ‘the gas radon is produced by the decay of uranium in rocks and soil’
      count noun ‘he developed a detector for decays of carbon-14’
      • ‘The half-life of radioactive matter is the time before half of any given amount of nuclei will break down through alpha decay.’
      • ‘Plutonium does not exist in nature but results from radioactive decay of uranium - 239.’
      • ‘The radioactive decay releases energy in the form of ionising radiation.’
      • ‘Radon is present in the atmosphere because it is constantly being formed during the radioactive decay of uranium and radium.’
      • ‘The principles of alpha decay are used in radioactive dating, in which half-lives play an important part.’
    5. 1.5technical Gradual decrease in the magnitude of a physical quantity.
      ‘the required time constant for current decay is 1 ms’
      • ‘Measurements of the decay of the electrical field across the thylakoid membrane following a light - dark transition might give some clues to this.’
      • ‘This is one order of magnitude slower than the decay of K in the bacteriorhodopsin photocycle.’
      • ‘After linear baseline subtraction, to account for the gradual decay of the synchrotron beam intensity, two kinds of treatments were performed.’
      • ‘In addition to slowing the decay of the tail currents at - 120 mV, there was a change in the relation of the second tail current to the first.’
      • ‘However, once again, the declining field strength is best explained by an exponential decay of the field due to a decaying electric current.’


Late Middle English: from Old French decair, based on Latin decidere ‘fall down or off’, from de- ‘from’ + cadere ‘fall’.