What does fallout mean?
Fallout is a noun with two closely related senses, both carrying strongly negative connotations. In its original, literal sense, fallout refers to the radioactive dust and debris that rises into the atmosphere during a nuclear explosion and gradually settles back to earth, contaminating land, water, and living things far from the blast site. From this technical meaning grew a widely used figurative sense: the unpleasant consequences or repercussions that follow a damaging event, as in 'the political fallout from the scandal' or 'the economic fallout of the crisis'. Today this second sense dominates everyday usage, appearing constantly in news reporting and public affairs. The word arose from the verb phrase 'fall out' and became prominent only after the advent of nuclear weapons testing in the mid-twentieth century. It is uncountable, taking no plural form, and pairs readily with modifiers such as 'radioactive' and 'political'. Its vivid physical imagery makes it a powerful way to describe aftermath and consequence.
The radioactive dust and debris that descends to the ground after a nuclear explosion.
"Fallout from the test spread hundreds of miles downwind."
Uncountable; the original, literal sense.
The unpleasant consequences or repercussions of an event or action.
"The fallout from the merger cost thousands of jobs."
Figurative sense; now the most common use.
Fallout is an uncountable noun and has no plural form; quantities are expressed periphrastically, e.g. 'widespread fallout' or 'measurable levels of fallout'.
"There was little measurable fallout beyond the test site."
The word 'fallout' barely existed before 1945 — nuclear weapons testing turned it from an obscure term into one of the defining anxieties of the twentieth century.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of fallout
Fallout derives from the English phrasal verb 'fall out', combining the native Germanic verb 'fall' (Old English 'feallan') with the adverbial particle 'out'. The compound noun emerged in the nineteenth century but rose to prominence after 1945, when atmospheric nuclear weapons testing made it the standard term for airborne radioactive debris settling to the ground. Its figurative use for the consequences of an event developed naturally from this literal sense. It shares its root with other native English compounds built on 'fall', such as 'downfall', 'rainfall', and 'shortfall'.
How fallout is actually used
Originally a technical term in nuclear science, the figurative sense ('political fallout', 'fallout from the scandal') is now by far the most common in everyday use. The word carries strongly negative connotations and functions almost exclusively as an uncountable noun; it takes no plural form.
Easily confused with fallout
An outfall is the mouth or pipe where a drain or sewer discharges into a river or sea, whereas fallout is radioactive debris or the negative consequences that follow an event.