chain reaction

noun

1

a

: a series of events so related to each other that each one initiates the next

b

: a number of events triggered by the same initial event

2

: a self-sustaining chemical or nuclear reaction yielding energy or products that cause further reactions of the same kind

chain-react

ˈchān-rē-ˈakt 

intransitive verb

Examples of chain reaction in a Sentence

Increased oil prices could trigger a chain reaction in the economy.

Recent Examples on the Web

By October 1939, the month Einstein’s letter was finally delivered to Roosevelt, the Diebner project was already gathering speed, with research into producing a chain reaction and building a bomb going on at numerous German universities. —Literary Hub, 23 Oct. 2025

The series of chain reaction events eventually grew to involve at least five vehicles with multiple injuries to other motorists, CHP officials said. —Caleb Lunetta, San Diego Union-Tribune, 23 Oct. 2025

The difference this time is the chain reaction. —Vitalii Savryha, Sourcing Journal, 21 Oct. 2025

Second, the flowing glacier brings more ice forward to replace what breaks off, slowing the cliff’s inland retreat and making a chain reaction of cliff toppling less likely. —Evan Howell, Quanta Magazine, 20 Oct. 2025

Word History

First Known Use

1892, in the meaning defined at sense 1a

Rhymes for chain reaction

• abstraction
• attraction
• compaction
• contraction
• detraction
• diffraction
• distraction
• exaction
• extraction
• impaction
• inaction
• infraction

Kids Definition

chain reaction

noun

1

: a series of events so related to each other that each one sets the next one going

2

: a chemical or nuclear reaction producing energy or products that cause further reactions of the same kind

Medical Definition

chain reaction

noun

: a self-sustaining chemical or nuclear reaction yielding energy or products that cause further reactions of the same kind