English Reference
noun

combustion

n.
US /kəmˈbəstʃən/ UK /kəmbˈʌstʃən/ com·bus·tion UK spelling combustions

  1. 01 C1 Advanced Technical Science

    the process of burning something.

    the chemical process of oxidation that occurs rapidly enough to produce heat and usually light.

    Simple

    The engine works by using the combustion of petrol to create power.

    In context

    Spontaneous combustion occurs when a substance ignites without an external heat source, typically due to internal chemical reactions that generate sufficient heat.

    Usage

    Often used as an uncountable noun in scientific descriptions, but countable when referring to specific instances or types of the process.

  2. 02 C2 Proficiency LiteraryFormal

    a state of great excitement, anger, or social trouble.

    a state of violent agitation, tumult, or social upheaval.

    Simple

    The city was in a state of combustion after the unfair trial.

    In context

    The political landscape was ripe for combustion, with decades of suppressed resentment finally reaching a flashpoint.

    Teacher's tip

    This figurative sense is rare in modern speech; it is primarily found in older literature or high-level political commentary.

Its engine's combustion results only in water vapor, with no carbon emissions.

Phys.org· 15 Aug 2026

The new record surpasses the previous official hydrogen combustion title set in 2004 by more than double the speed.

BBC News· 12 Aug 2026

From Old French combustion, from Latin combustio, from comburere (“to burn”), itself from the intensifying prefix com- + the root burere (a faulty sep. of amburere "to burn around", itself from ambi- + urere "to burn, singe"); equivalent to combust + -ion.

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

This entry
Origin Latin combustio
Level C1 · Advanced
Frequency Frequent
Updated