decay

[ dih-key ]

See synonyms for: decay decayed decaying on Thesaurus.com

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

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; see de-.

synonym study For decay

1. 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 words for decay

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

See synonyms for decay on Thesaurus.com

Other words from decay

de·cay·a·ble, adjective
de·cayed·ness [dih-keyd-nis, -key-id-], /dɪˈkeɪd nɪs, -ˈkeɪ ɪd-/, adjective
de·cay·less, adjective
non·de·cayed, adjective
non·de·cay·ing, adjective
re·de·cay, verb
sem·i·de·cay, noun
sem·i·de·cayed, adjective
un·de·cay·a·ble, adjective
un·de·cayed, adjective
un·de·cay·ing, adjective

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2023

How to use decay in a sentence

Heat from the decay of radioactive materials, he suggested, sets this layer to a slow boil, creating large circulating currents within the molten rock that in turn slowly shift the continents about.
How the Earth-shaking theory of plate tectonics was born | Carolyn Gramling | January 13, 2021 | Science News
The device would draw in ethylene, a gas emitted by plants that speeds up decay, and convert it into water and carbon dioxide, which help plants grow.
Air purifier company seeks emergency FDA approval for device that rids indoor air of virus | Dalvin Brown | December 10, 2020 | Washington Post
The reality of the instrument’s decay had become fully apparent in November, after the National Science Foundation reviewed two recent cable breaks and decided to decommission the world-class radio telescope.
The Arecibo Observatory collapsed this week. What now? | Charlie Wood | December 4, 2020 | Popular-Science
I’d been studying radioactive decay in my courses, and Bill suggested we work together on calculating the lifetimes of new chemical elements, heavier than those in the known Periodic Table.
Five Scientists on the Heroes Who Changed Their Lives - Issue 93: Forerunners | Alan Lightman, Hope Jahren, Robert Sapolsky, | December 2, 2020 | Nautilus
Ten come from radioactive decay in the detector materials, and in this particular energy range about three come from the sun’s main fusion reaction.
We still don’t really know what’s inside the sun—but that could change very soon | Charlie Wood | November 30, 2020 | Popular-Science

These new dark ages stem from a corrupt and decaying power system—a reflection of the state of affairs in the country itself.
Who Will Maduro Blame for Venezuela’s Blackout This Time? | Daniel Lansberg-Rodríguez | June 28, 2014 | THE DAILY BEAST
Their loved ones would visit, tending to their decaying relatives, even changing their clothing.
Palermo Has an Underground City Filled With Its Mummified Dead | Nina Strochlic | May 1, 2014 | THE DAILY BEAST
A decaying statue of St. Lucia, patron saint of the blind, holds a platter with two eyes.
The Sacrificial Limbs of New Orleans | Nina Strochlic | March 12, 2014 | THE DAILY BEAST
Erica is the foil to the unstable, decaying Beth—a kind, virtuous, smooth-skinned girl next door.
Anna Kendrick: Queen Bee of the 2014 Sundance Film Festival | Marlow Stern | January 23, 2014 | THE DAILY BEAST
Of course, there are limits to building a candidacy on the decaying pillar of labor.
What’s Elizabeth Warren Up To Now? | Daniel Gross | September 10, 2013 | THE DAILY BEAST
This explanation seemed very likely, for here and there were stumps of trees and decaying chips.
The Box-Car Children | Gertrude Chandler Warner
So far as we know, we can perceive no certain method by which the life of the slowly decaying suns can be restored.
Outlines of the Earth's History | Nathaniel Southgate Shaler
Cotgrave gives us: 'Faillance, f. a defection, failing, decaying.'
Chaucer's Works, Volume 1 (of 7) -- Romaunt of the Rose; Minor Poems | Geoffrey Chaucer
Decaying nature could no longer be recruited by ordinary sources of strength and sustenance.
The History of England in Three Volumes, Vol.III. | E. Farr and E. H. Nolan
The fir-trees died, and added to the great masses of decaying wood which now covered the damp ground.
Our Little Irish Cousin | Mary Hazelton Wade

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

Also: disintegrate (intr) physics
- (of an atomic nucleus) to undergo radioactive disintegration
- (of an elementary particle) to transform into two or more different elementary particles
(intr) 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
physics a gradual decrease of a stored charge, magnetic flux, current, etc, when the source of energy has been removed: See also time constant
music the fading away of a note

Origin of decay

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

Derived forms of decay

decayable, adjective

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

Scientific definitions for decay

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.

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