spontaneous combustion

American  

noun

1. the ignition of a substance or body from the rapid oxidation of its own constituents without heat from any external source.

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spontaneous combustion British  

noun

1. the ignition of a substance or body as a result of internal oxidation processes, without the application of an external source of heat, occurring in finely powdered ores, coal, straw, etc

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spontaneous combustion Scientific  

1. The bursting into flame of a mass of material as a result of chemical reactions within the substance, without the addition of heat from an external source. Oily rags and damp hay, for example, are subject to spontaneous combustion.

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spontaneous combustion Cultural  

1. A process by which a collection of materials (such as oily rags) catches fire without the application of heat from outside. The oxidation of substances in the materials starts the fire.

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Etymology

Origin of spontaneous combustion

First recorded in 1800–10

Example Sentences

They were also located in a layer that lacked guano deposits, ruling out spontaneous combustion as an explanation.

From Science Daily • Jun. 24, 2026

"So it started with that flame. It was like spontaneous combustion."

From BBC • Mar. 17, 2026

This can happen for reasons ranging from spontaneous combustion to human irresponsibility.

From Salon • Mar. 4, 2023

In this delightfully outrageous tale, Holmes and sidekick John Watson must determine how and why four government officials have died through spontaneous combustion.

From Washington Post • Dec. 17, 2022

I thought of theory number five: spontaneous combustion.

From "The London Eye Mystery" by Siobhan Dowd