decay
dih-KAY
Decay (verb) means to rot or gradually break down, especially of organic matter. Example: “The fallen leaves slowly decayed into the soil.”
verb
1
To rot or gradually break down, especially of organic matter.
"The fallen leaves slowly decayed into the soil."
"Without treatment, the tooth will continue to decay."
2
To decline gradually in quality, strength, or condition.
"The old empire's power decayed over several centuries."
noun
1
The process or result of rotting or gradual deterioration.
"The building showed signs of decay after years of neglect."
"Tooth decay is largely preventable with good brushing habits."
2
In physics, the process by which an unstable atomic nucleus or particle breaks down over time.
"Scientists measured the radioactive decay of the isotope."
How to use decay
Learner’s notesIn plain EnglishTo rot or gradually get worse — used for teeth, buildings, empires, and even radioactive atoms.
Common pairings
tooth decay
radioactive decay
fall into decay
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Word forms
- Plural
- decays
- Third person singular
- decays
- Past tense
- decayed
Fill the gap
Can you complete this real example?
The fallen leaves slowly _____ into the soil.
Etymology
From Anglo-Norman decaeir, ultimately from Latin dē- ("down, away") + cadere ("to fall") — the same root as "decadent" and "decadence."
Synonyms
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Rhymes for decay
See all rhymes for decay →Frequently asked questions
What does “decay” mean?
The word “decay” means to rot or gradually break down, especially of organic matter. In plain terms, to rot or gradually get worse — used for teeth, buildings, empires, and even radioactive atoms.
How do you pronounce “decay”?
“Decay” is pronounced dih-KAY (/diˈkeɪ/ in IPA).
How do you use “decay” in a sentence?
Here is “decay” used in a sentence: “The fallen leaves slowly decayed into the soil.”
What is another word for “decay”?
Words with a similar meaning to “decay” include fester.
What part of speech is “decay”?
Depending on how it is used, “decay” can be a verb and a noun.
Where does the word “decay” come from?
The word “decay” comes from Latin. From Anglo-Norman decaeir, ultimately from Latin dē- ("down, away") + cadere ("to fall") — the same root as "decadent" and "decadence.".
Is “decay” a common word?
“Decay” is a fairly common word in modern English, usually learned at around the B2 level.
How many meanings does “decay” have?
“Decay” has 4 distinct senses listed in this dictionary. The most common is: to rot or gradually break down, especially of organic matter.
What is the difference between decay and rot?
Decay is the broader term, covering both the gradual breakdown of organic matter and the decline of quality, strength, or condition in non-organic things like buildings or institutions. Rot specifically refers to organic decomposition and is essentially one type of decay.
What does decay mean in physics?
In physics, decay describes the process by which an unstable atomic nucleus or particle breaks down over time, releasing energy or particles as it transforms into a more stable state. This is a specialized, technical use distinct from decay's everyday meaning of rotting or declining.
Can decay be used for things other than physical objects?
Yes, decay is commonly used figuratively to describe the gradual decline in quality, strength, or condition of abstract things, such as moral decay or the decay of a relationship, not just physical or organic breakdown.
