English Reference
Noun

decomposition

n. uncountable
B2 Upper Intermediate US /ˌdikəmpəˈzɪʃən/ UK /dˌiːkɒmpəzˈɪʃən/ de·com·po·si·tion UK spelling decomposition's, decomposition's

n.the natural process of dead plants or animals breaking down and rotting. It is how nature recycles nutrients back into the soil.

n.the biological and chemical process by which organic substances are broken down into simpler matter. Often involves the action of bacteria or fungi and is essential for nutrient cycling in ecosystems.


SIMPLE

The decomposition of leaves provides nutrients for the forest floor.

CONTEXTUAL

Scientists studied the rate of decomposition in the swamp to understand how carbon is stored in the mud.

COMPLEX

In forensic science, the specific stages of decomposition can provide investigators with a reliable timeline for estimating the interval since a biological organism ceased to function.

Usage

Primarily uncountable when referring to the general process; can be countable in technical contexts referring to specific chemical breakdowns.

Study: Land use is the biggest factor in determining decomposition rates of organic cotton underpants.

Ars Technica· 27 Aug 2026

When their blooms die, their decomposition depletes oxygen in the water, creating so-called dead zones.

The Guardian· 14 Aug 2026

From de- + composition.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level B2 · Upper Intermediate
Frequency Frequent
Updated