decompose

American  

[dee-kuhm-pohz] / ˌdi kəmˈpoʊz /

verb (used with object)

decomposed, decomposing

1. to separate or resolve into constituent parts or elements; disintegrate.

   The bacteria decomposed the milk into its solid and liquid elements.

   Synonyms:

   analyze, fractionate, distill

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verb (used without object)

decomposed, decomposing

1. to rot; putrefy.

   The egg began to decompose after a day in the sun.

decompose British  

/ ˌdiːkəmˈpəʊz, ˌdiːkɒmpəˈzɪʃən /

verb

1. to break down (organic matter) or (of organic matter) to be broken down physically and chemically by bacterial or fungal action; rot

2. chem to break down or cause to break down into simpler chemical compounds

3. to break up or separate into constituent parts

4. (tr) maths to express in terms of a number of independent simpler components, as a set as a canonical union of disjoint subsets, or a vector into orthogonal components

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Related Words

See decay.

Other Word Forms

• decomposability noun
• decomposable adjective
• decomposition noun
• undecomposable adjective

Etymology

Origin of decompose

1745–55; < French décomposer, equivalent to dé- dis- ¹ + composer to compose

Explanation

The verb decompose means to break down or decay, like tree leaves that decompose into dirt, or cell phone batteries that decompose, resulting in more frequent charging for the user. You know that the prefix de- means "remove" or "undo." And something that's composed is made up of parts. So to decompose is to undo all the parts until they go back to their original state: dirt. Living things decompose. When things like buildings or organizations break down, you typically use words like dismantle or deconstruct to describe the process.

Example Sentences

Despite recycling efforts, most plastic ends up in landfills where it can take centuries to decompose, leaching out chemicals during that time, Deeney said.

From Barron's • Jan. 26, 2026

This creates a powerful feedback loop: more nutrients lead to more algae, which consume more oxygen as they decompose, which in turn releases even more nutrients.

From Science Daily • Nov. 2, 2025

The shells serve a dual purpose — one that is functional, as they decompose to improve the soil quality, and another formal, reflecting moonlight in the evening.

From Los Angeles Times • Apr. 4, 2025

The upper layers of soil contain more active microbes, so bodies can decompose in about 20 to 30 years, rather than up to 100 in a traditional grave.

From BBC • Dec. 14, 2024

Despite being embalmed, the body began to decompose and smell by Thursday, three days after Garfield's death.

From "Ambushed!" by Gail Jarrow

Related Words

• break down
• decay
• disintegrate
• dissolve
• fall apart
• molder