decay

[dih-key]

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

/ 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

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

decay

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.

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

Word History and Origins

Origin of decay¹

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-.

Word History and Origins

Origin of decay¹

C15: from Old Northern French decaïr, from Late Latin dēcadere, literally: to fall away, from Latin cadere to fall

Synonym Study

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.

Example Sentences

Earlier temperature estimates had been uncertain, often distorted by motion within the plasma that created Doppler-like shifts or by confusion about whether the readings reflected the plasma itself or later stages of its decay.

Read more on Science Daily

A feeble exit from the Champions League, flat domestic performances, a stench of decay in the air.

Read more on BBC

In 1986, a group of locals, upon learning the government planned to sell the rapidly decaying beacon as scrap, started the St. George Reef Lighthouse Preservation Society.

Read more on Los Angeles Times

The energy shortage and infrastructures’ extreme decay were both obvious for some time.

Read more on MarketWatch

Do American cities host concerts, art exhibits and pro sports events to distract from local crime and urban decay?

Read more on The Wall Street Journal

Related Words

• atrophy 
• corrode 
• decompose 
• degenerate 
• discolor 
• disintegrate 
• dissolve 
• dwindle 
• fade 
• get worse www.thesaurus.com
• lessen 
• mortify 
• pollute 
• rot 
• shrivel 
• wane 
• wither