Dictionary.com
Thesaurus.com
Synonyms

decay

American  
[dih-key] / dɪˈkeɪ /

verb (used without object)

  1. to become decomposed; rot.

    vegetation that was decaying.

    Synonyms:
    putrefy, wither, degenerate
  2. to decline in excellence, prosperity, health, etc.; deteriorate.

  3. Physics. (of a radioactive nucleus) to change spontaneously into one or more different nuclei in a process in which atomic particles, as alpha particles, are emitted from the nucleus, electrons are captured or lost, or fission takes place.


verb (used with object)

  1. to cause to decay or decompose; rot.

    The dampness of the climate decayed the books.

noun

  1. decomposition; rot.

    Decay made the wood unsuitable for use.

    Synonyms:
    putrefaction
  2. a gradual falling into an inferior condition; progressive decline.

    the decay of international relations; the decay of the Aztec civilizations.

  3. decline in or loss of strength, health, intellect, etc..

    His mental decay is distressing.

    Synonyms:
    degeneration, dilapidation, impairment, decadence, deterioration
  4. Physics. radioactive decay.

  5. Aerospace. the progressive, accelerating reduction in orbital parameters, particularly apogee and perigee, of a spacecraft due to atmospheric drag.

decay British  
/ dɪˈkeɪ /

verb

  1. to decline or cause to decline gradually in health, prosperity, excellence, etc; deteriorate; waste away

  2. to rot or cause to rot as a result of bacterial, fungal, or chemical action; decompose

  3. Also: disintegrate(intr) physics

    1. (of an atomic nucleus) to undergo radioactive disintegration

    2. (of an elementary particle) to transform into two or more different elementary particles

  4. (intr) physics (of a stored charge, magnetic flux, etc) to decrease gradually when the source of energy has been removed

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012

noun

  1. the process of decline, as in health, mentality, beauty, etc

  2. the state brought about by this process

  3. decomposition, as of vegetable matter

  4. rotten or decayed matter

    the dentist drilled out the decay

  5. physics

    1. See radioactive decay

    2. a spontaneous transformation of an elementary particle into two or more different particles

    3. of an excited atom or molecule, losing energy by the spontaneous emission of photons

  6. physics a gradual decrease of a stored charge, magnetic flux, current, etc, when the source of energy has been removed See also time constant

  7. music the fading away of a note

"Collins English Dictionary — Complete & Unabridged" 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
decay Scientific  
/ dĭ-kā /
  1. The breaking down or rotting of organic matter through the action of bacteria, fungi, or other organisms; decomposition.

  2. The spontaneous transformation of a relatively unstable particle into a set of new particles. For example, a pion decays spontaneously into a muon and an antineutrino. The decay of heavy or unstable atomic nuclei (such as uranium or carbon-10) into more stable nuclei and emitted particles is called radioactive decay. The study of particle decay is fundamental to subatomic physics.

  3. See more at fundamental force radioactive decay


  1. To undergo decay.

Related Words

Decay, decompose, disintegrate, rot imply a deterioration or falling away from a sound condition. Decay implies either entire or partial deterioration by progressive natural changes: Teeth decay. Decompose suggests the reducing of a substance to its component elements: Moisture makes some chemical compounds decompose. Disintegrate emphasizes the breaking up, going to pieces, or wearing away of anything, so that its original wholeness is impaired: Rocks disintegrate. Rot is a stronger word than decay and is especially applied to decaying vegetable matter, which may or may not emit offensive odors: Potatoes rot.

Other Word Forms

  • decayable adjective
  • decayedness adjective
  • decayless adjective
  • nondecayed adjective
  • nondecaying adjective
  • redecay verb
  • semidecay noun
  • semidecayed adjective
  • undecayable adjective
  • undecayed adjective
  • undecaying adjective

Etymology

Origin of decay

First recorded in 1425–75; late Middle English verb decayen, decaien, from Old North French decair, equivalent to de- “down” + cair “to fall,” from unattested Vulgar Latin cadēre, for Latin cadere; noun derivative of the verb; de-.

Example Sentences

Examples are provided to illustrate real-world usage of words in context. Any opinions expressed do not reflect the views of Dictionary.com.

Mr. Wright suggests this is less a “crisis” or a “collapse” than a “prolonged decay,” which is apt.

From The Wall Street Journal

These components are critical for accurately tracking particle decays and identifying signals such as the Ξcc⁺.

From Science Daily

“They are seeing a decaying system before their eyes,” said Nadimi.

From The Wall Street Journal

That meant he dearly loved rolling in manure and decay, so Tarbox territory was the happy hunting ground for him.

From Literature

This gives scientists a brief chance to measure how the more stable elements decay, then deduce the properties of the original particle.

From Barron's