chemical reaction

American  

[kem-i-kuhl ree-ak-shuhn] / ˈkɛm ɪ kəl riˈæk ʃən /

noun

1. Chemistry. reaction.

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chemical reaction British  

noun

1. a process that involves changes in the structure and energy content of atoms, molecules, or ions but not their nuclei Compare nuclear reaction

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chemical reaction Cultural  

1. A process in which atoms of the same or different elements rearrange themselves to form a new substance. While they do so, they either absorb heat or give it off.

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Etymology

Origin of chemical reaction

First recorded in 1780–90

Example Sentences

The leak also depletes the source for a chemical reaction, which is generating heat that, in turn, accelerates the reaction in a process called “thermal runaway.”

From Los Angeles Times • May 24, 2026

Hydrogen sulfide smells like rotten eggs and can be produced by a chemical reaction and by some organic material, such as sewage.

From The Wall Street Journal • Apr. 22, 2026

Fire Administration, potentially leading to a process known as thermal runaway, in which the battery ignites through a self-sustaining chemical reaction that is impossible to stop until it runs out on its own.

From Los Angeles Times • Apr. 6, 2026

Form’s iron-air batteries generate electricity through a chemical reaction involving oxygen, water and iron powder that mimics how old pieces of metal gather rust.

From Barron's • Feb. 24, 2026

“It’s all household stuff. Baking soda. Stuff like that. My cousin told me how. It’s a chemical reaction, but it’s harmless stuff.”

From "Popcorn" by Rob Harrell

Related Words

• vicious circle