decompose

decompose — verb

1. When a dead plant, animal, or other organic material decomposes, it naturally br

1.verbtransitive / intransitiveB2
Definition

When a dead plant, animal, or other organic material decomposes, it naturally breaks down into simpler substances through the action of bacteria, fungi, or other microorganisms.

Example

The wooden fence at Hao's farm started to decompose after years of rain and wind.

intransitive use: organic material + decompose (no object needed)

Yara placed the vegetable scraps in a compost bin so they would decompose naturally.

purpose clause: place [obj] in [place] so [subj] will decompose

Common collocations
  • decompose rapidly
  • decompose slowly
  • partially decompose
  • completely decompose
  • organic matter
  • dead leaves
  • dead animals
  • plant material
  • kitchen waste
  • compost heap
Synonyms
  • rot

    more common in everyday speech; implies unpleasant smell and visible decay

  • decay

    slightly less formal than decompose; can also apply to teeth or buildings

  • putrefy

    technical term for the stage of decomposition that produces foul odors; rare in everyday use

Antonyms
  • compose

    to form or make up something by putting parts together — the opposite process

  • preserve

    to prevent decay, as in embalming or pickling

Grammar Patterns

something + decompose (intransitive)

decompose + something (transitive)

decompose + into + something

Usage Note

Frequently used intransitively in scientific writing about natural processes. More formal than 'rot' or 'decay'; preferred in biology and environmental science contexts.

Common Mistakes

The meat decomposed because I forgot to put it in the fridge.' (unnatural — 'go bad' or 'rot' is more natural for everyday food spoilage).
The meat went bad because I left it out of the fridge.
'decompose' sounds too technical for everyday food spoilage.

2. To separate a substance into the simpler substances it is made of, especially by

2.verbtransitive / intransitiveB2
Definition

To separate a substance into the simpler substances it is made of, especially by a chemical process such as heating, adding a reagent, or passing an electric current through it.

Example

Heating blue powder in the lab decomposed it into a black solid and gas.

transitive use: heat + decompose + [obj] + into + [result]

Christopher used an electric current to decompose water into hydrogen and oxygen.

infinitive of purpose: use [method] to decompose [substance] into [parts]

Common collocations
  • decompose into
  • decompose by heating
  • decompose through electrolysis
  • chemically decompose
  • decompose a compound
  • decompose a substance
  • decompose water
  • decompose light
Synonyms
  • break down

    much more common in everyday English; less formal and less precise scientifically

  • separate

    broader in meaning; does not necessarily imply chemical change

  • disintegrate

    emphasizes falling apart into pieces rather than chemical transformation

Antonyms
  • synthesize

    to build up a compound from simpler substances

  • combine

    to join substances together into a single material

Grammar Patterns

decompose + something + into + something

something + decomposes + into + something (intransitive)

use [method] to decompose [substance]

Usage Note

Commonly used in chemistry and materials science. Often transitive with a scientist or process as the subject. The resulting parts are typically introduced by 'into'.

Common Mistakes

I decomposed the problem into three parts.' (too metaphorical in everyday English).
I broke the problem down into three parts.
'decompose' is not used for abstract division in everyday speech.

Word family

Synonym discussion

Sense: verb/1

Decompose, rot, decay, putrefy, and spoil all describe organic matter breaking down after death, but they differ in formality and focus. Decompose is the most neutral and scientific term, used broadly for the natural breakdown of dead plants or animals by bacteria and fungi. Decay is more general and slightly less formal, often suggesting a gradual loss of quality or structure — a tooth can decay, a building can decay. Rot is the most everyday word, carrying a strong association with unpleasant smell and visible damage: rotten fruit smells bad and looks disgusting. Putrefy is a technical term for the later stage of decomposition where foul odours are produced; it is rarely used outside biology. Spoil applies to food that has become unfit to eat, like milk that has gone sour. In everyday conversation, say 'The fruit rotted in the bowl.' In a science report, say 'The organic matter decomposed within two weeks.'

rotdecay ↗putrefyspoil ↗

Common collocations

Nouns

Adverbs

Phrases

  • decompose over time
  • begin to decompose
  • cause something to decompose
  • leave something to decompose

Prepositions

Etymology

LatinFrenchEnglish

Decompose comes from the Latin prefix 'de-' meaning 'down, away, apart' combined with 'componere' meaning 'to put together' — so literally 'to un-put-together,' or to separate what was assembled. It entered English through French in the mid-1600s, first in the general sense of separating a whole into its parts, and later became the standard term for biological rotting. The modern scientific contrast with 'compose' (to put together) reflects this Latin origin.