decomposition
American-
The separation of a substance into simpler substances or basic elements. Decomposition can be brought about by exposure to heat, light, or chemical or biological activity.
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The process of breaking down organic material, such as dead plant or animal tissue, into smaller molecules that are available for use by the organisms of an ecosystem. Decomposition is carried on by bacteria, fungi, protists, worms, and certain other organisms.
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See more at detritivore
Etymology
Origin of decomposition
1650–60; probably < French décomposition, derivative of décomposer to decompose; see composition
Explanation
Decomposition is the process of decaying or rotting. If you've ever left a carved pumpkin on the porch into late November, you have seen and smelled decomposition. A "composition" is a paper or group of items that's put together, while a decomposition is a breaking down or coming apart. You can use the noun decomposition for rotting plants and animals. Some people keep a compost pile for trash decomposition, which produces fertilizer. Studying decomposition lets you see the different stages of rotting, and science teachers often let students leave out a piece of fruit on purpose, just to watch its decomposition and the growth of maggots.
Vocabulary lists containing decomposition
Earth Science - Middle School
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The Carbon Cycle
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Earth Science - High School
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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.
Brian Eckenrode, a retired FBI forensic scientist and expert in human decomposition, joined them in 2021.
From Los Angeles Times • May 6, 2026
A body was found in scrubland in 2007, the state of decomposition indicating it had been there for decades.
From BBC • Apr. 29, 2026
"This hydrogen peroxide decomposition has been used to power large-scale rockets," says Erica Hastings, PhD, postdoctoral fellow in biochemistry in the SFESOM.
From Science Daily • Mar. 19, 2026
As decomposition speeds up, more CO2 from this enormous carbon store could enter the atmosphere.
From Science Daily • Feb. 24, 2026
Mr. Mams had asked her to perform a chemical experiment that had to do with the decomposition of organic materials.
From "October Sky" by Homer Hickam
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Definitions and idiom definitions from Dictionary.com Unabridged, based on the Random House Unabridged Dictionary, © Random House, Inc. 2023
Idioms from The American Heritage® Idioms Dictionary copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.