chain reaction

What it means

A chain reaction is a series of events in which each one directly triggers the next, creating an unbroken sequence of consequences. The phrase is used in physics, chemistry, and economics, and in everyday talk about pileups, layoffs, or social movements where one event sets off many more.

Examples

• One small mistake set off a chain reaction in the production line.
• His resignation triggered a chain reaction across the department.
• The bank failure caused a chain reaction in regional markets.
• A single fender-bender on the highway can start a chain reaction of crashes.

Where it comes from

A 20th-century scientific term, originally describing nuclear fission and chemical processes in which one reaction provides the conditions for the next. The figurative use for cascading social or business events spread after World War II.

Related idioms