Definition of decay in English:


Line breaks: decay
Pronunciation: /dɪˈkeɪ


[no object]


[mass noun] Back to top  
  • 1The state or process of rotting or decomposition: hardwood is more resistant to decay than softwood tooth decay
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    • Irregular and improper brushing, not flossing between teeth and not rinsing the mouth after meals, speed up the process of tooth decay.
    • The most common type of tooth damage is decay, caused by a combination of poor toothbrushing and a sugary diet.
    • A child's first set of teeth are just as important as their adult teeth and tooth decay at an early age can affect the development of permanent teeth.
  • 1.1Rotten matter or tissue: fluoride heals small spots of decay
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    • However, too much growth produces a strain on tissues and early decay.
    • 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.
  • 1.2Structural or physical deterioration: the old barn rapidly fell into decay
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    • The home fell into decay by the start of the 1970s.
    • Gradually the abandoned buildings fell into decay or were adopted for other uses.
    • The home is still empty today, and has suffered considerable interior damage, including structural decay resulting from water leaks in the building.
  • 1.3The process of declining in quality, power, or vigour: the problems of urban decay
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    • ‘Together let us find solutions to moral decay by jointly developing a strategy and a programme of action,’ Masondo says.
    • People talk a lot about cultural decay and declining values and the blame is usually placed on evil liberals.
    • For Webster's audience, Italy was perceived as a site of political intrigue, economic power, decadence, and moral decay.
  • 1.4 Physics 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
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    • The radioactive decay releases energy in the form of ionising radiation.
    • The principles of alpha decay are used in radioactive dating, in which half-lives play an important part.
    • Radon is present in the atmosphere because it is constantly being formed during the radioactive decay of uranium and radium.
  • 1.5 technical Gradual decrease in the magnitude of a physical quantity: the required time constant for current decay is 1 ms
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    • After linear baseline subtraction, to account for the gradual decay of the synchrotron beam intensity, two kinds of treatments were performed.
    • 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.


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

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