Meaning
A sequence of events in which each one causes or triggers the next, so the process feeds itself and accelerates - from chemistry and nuclear physics, where it is literal, to bank runs, revolutions, and office gossip, where it is the standard figure for self-propagating trouble. Neutral in science, ominous in finance and politics - it implies the process, once started, will not stop on its own; near-neighbours domino effect and snowball effect carry lighter and slower pictures. Regional use: General English; chemistry and physics origin.
Origin
Chemistry built the term. Max Bodenstein first put forward the idea of chemical chain reactions in 1913, Walther Nernst applied it to the hydrogen-chlorine reaction in 1918, Christiansen and Kramers proposed chain branching in 1923, and Nikolai Semyonov's quantitative theory earned the 1956 Nobel Prize, shared with Cyril Hinshelwood. Physics then gave the phrase its awesome second life: Leo Szilard proposed a nuclear chain reaction in 1933, five years before fission was discovered; he and Enrico Fermi proved the neutron-multiplying reaction in uranium in 1939; and Fermi's team demonstrated the first self-sustaining chain reaction at Chicago Pile-1 in late 1942, the principle of reactors and bombs alike. The figurative sense followed the headlines, and though the freely consulted sources print no dated first citation for it, Wiktionary's record runs from the Manhattan Project's first controlled chain reaction to a 2010 finance text describing systemic risk as a chain reaction of falling, interconnected dominos.
Research Sources
References used to check this entry’s meaning, history, or documented forms.
Variants
- chain reactions
- set off a chain reaction
- trigger a chain reaction
Usage Examples
- One bank run set off a chain reaction that reached three currencies before the central bank intervened.
- The resignation triggered a chain reaction of deputy departures, each citing the last.
- Chemistry students reproduce a tame chain reaction every term; history does it without supervision.