chemical reaction

American  

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

noun

1. Chemistry. reaction.

---

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

---

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.

---

Etymology

Origin of chemical reaction

First recorded in 1780–90

Example Sentences

See Examples For:

chemical reaction

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

The crystals are driven by a chemical reaction similar to the one used to power rockets.

From Science Daily ● Mar. 19, 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

Industrial catalysts -- substances that reduce the amount of energy required for a given chemical reaction -- help manufacturers boost reaction speed, yield or efficiency when producing key materials.

From Science Daily ● Nov. 21, 2025

Even worse, though, a chemical reaction that was occurring in the high heat of the reactor core was producing highly flammable hydrogen gas.

From "Meltdown" by Deirdre Langeland

Related Words

• vicious circle