decay

[dih-key] /dɪˈkeɪ/

verb (used without object)

to become decomposed; rot:

vegetation that was decaying.

to decline in excellence, prosperity, health, etc.; deteriorate.

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)

to cause to decay or decompose; rot:

The dampness of the climate decayed the books.

noun

decomposition; rot:

Decay made the wood unsuitable for use.

a gradual falling into an inferior condition; progressive decline:

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

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

His mental decay is distressing.

Also called disintegration, radioactive decay. Physics. a radioactive process in which a nucleus undergoes spontaneous transformation into one or more different nuclei and simultaneously emits radiation, loses electrons, or undergoes fission.

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

Origin

1425-75; (v.) late Middle English decayen < Old North French decair, equivalent to de- de- + cair to fall < Vulgar Latin *cadēre, for Latin cadere; (noun) late Middle English, derivative of the v.

Related forms

decayable, adjective

decayedness

[dih-keyd-nis, -key-id-] /dɪˈkeɪd nɪs, -ˈkeɪ ɪd-/ (Show IPA), adjective

decayless, adjective

nondecayed, adjective

nondecaying, adjective

redecay, verb

semidecay, noun

semidecayed, adjective

undecayable, adjective

undecayed, adjective

undecaying, adjective

Synonyms

1. degenerate, wither; putrefy. 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. 5. putrefaction. 7. deterioration, decadence, impairment, dilapidation, degeneration.

Examples from the web for decay

If you make a four-season garden you have to learn to accept decay and see the beauty of it.
And along with this physical decay comes spiritual sickness.
The chemicals of decay were sampled by three collectors inserted through holes in the plastic sheet.
We have hung pigs in trees to see how decay differs from when the animal rests on the ground.
Today, according to these studies, the incidence of tooth decay is universally low regardless of fluoridation.
His first subjects were people he would see on the streets and rusty machinery that he felt captured society in decay.
With dental decay now less troublesome, more people are turning their attention to improving the appearance of their teeth.
Many studies demonstrate the retention decay rate of information delivered by lecture.
The radioactive decay that produces this heat produces neutrinos, too.
Four main factors affect the pace and completeness of decay.

British Dictionary definitions for decay

decay

/dɪˈkeɪ/

verb

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

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

(intransitive) (physics) Also disintegrate

(of an atomic nucleus) to undergo radioactive disintegration
(of an elementary particle) to transform into two or more different elementary particles

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

noun

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

the state brought about by this process

decomposition, as of vegetable matter

rotten or decayed matter: the dentist drilled out the decay

(physics)

See radioactive decay
a spontaneous transformation of an elementary particle into two or more different particles
of an excited atom or molecule, losing energy by the spontaneous emission of photons

10.

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

11.

(music) the fading away of a note

Derived Forms

decayable, adjective

Word Origin

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

Word Origin and History for decay

late 15c., "to decrease," from Anglo-French decair, Old North French decair (Old French decheoir, 12c., Modern French déchoir) "to fall, set (of the sun), weaken, decline, decay," from Vulgar Latin *decadere "to fall off," from de- (see de-) + Latin cadere "to fall" (see case (n.1)). Meaning "decline, deteriorate" is c.1500; that of "to decompose, rot" is from 1570s. Related: Decayed; decaying.

mid-15c., "deterioration, decline in value," from decay (v.). Meaning "gradual decrease in radioactivity" is from 1897.

decay in Medicine

decay de·cay (dĭ-kā')
n.

The destruction or decomposition of organic matter as a result of bacterial or fungal action; rot.
Dental caries.
The loss of information that was registered by the senses and processed into the short-term memory system.
Radioactive decay.

v. de·cayed, de·cay·ing, de·cays

To break down into component parts; rot.
To disintegrate or diminish by radioactive decay.
To decline in health or vigor; waste away.

decay in Science

decay

(dĭ-kā')
Noun

The breaking down or rotting of organic matter through the action of bacteria, fungi, or other organisms; decomposition.
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. See more at fundamental force, radioactive decay.

Verb To undergo decay.

decay in Technology

[Nuclear physics] An automatic conversion which is applied to most array-valued expressions in C; they "decay into" pointer-valued expressions pointing to the array's first element. This term is not used in the official standard for the language.
[Jargon File]