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

According to The Information, incident began when an engineer used an internal agent tool to analyze a technical question; the agent then posted advice without approval, which another employee followed, setting off a chain reaction that opened access to restricted systems. —Sharon Goldman, Fortune, 19 Mar. 2026

Cutting out carbohydrates can also disrupt your thyroid hormones, and this can lead to a sort of chain reaction in your body. —Maggie O'Neill, Verywell Health, 16 Mar. 2026

All of which has started to generate some essential change, though just how the Chiefs execute the presumptive chain reaction will be pivotal to how effective this initial burst becomes. —Kansas City Star, 16 Mar. 2026

Below, experts break down why being stressed or anxious can set off such a chain reaction in the first place and share ways to break free—or prevent irregular stress poops entirely. —Erica Sloan, SELF, 13 Mar. 2026

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