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.

---

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

---

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.

---

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.

---

Etymology

Origin of spontaneous combustion

First recorded in 1800–10

Example Sentences

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

From BBC • Mar. 17, 2026

Two years ago, Chairman Wang Chuanfu touted BYD's Blade battery, saying it would "guide the global battery industry back on track" and "put an end to spontaneous combustion" in EVs.

From Reuters • Jun. 30, 2022

It is not a party, it is not a feast, it is not even an orgy; it is simply the spontaneous combustion of a bunch of people having a good time.

From Scientific American • Mar. 31, 2022

All that heat is grilling brush and small trees practically to the point of spontaneous combustion, priming them for the smallest spark.

From Salon • Sep. 24, 2021

This myth about spontaneous combustion would be accepted as scientific fact far longer than might be imagined.

From "1919 The Year That Changed America" by Martin W. Sandler