fallout

1 of 2

noun

fall·​out ˈfȯl-ˌau̇t 

1

a

: the often radioactive particles stirred up by or resulting from a nuclear explosion and descending through the atmosphere

also : other polluting particles (such as volcanic ash) descending likewise

b

: descent (as of fallout) through the atmosphere

2

: a secondary and often lingering effect, result, or set of consequences

… have to take a position and accept the political fallout …

—Andy Logan

fall out

2 of 2

verb

fell out; fallen out; falling out; falls out

intransitive verb

1

: quarrel

also : to cut off relations over a quarrel

former friends who have fallen out

2

: turn out, happen

I expected to be in the States …, but things fell out otherwise.

—Mark Twain

3

a

: to leave one's place in the ranks

b

: to leave a building in order to take one's place in a military formation

Synonyms of fallout

Verb

• bicker
• fight
• argue
• spat
• quarrel
• clash

Examples of fallout in a Sentence

Noun

concerned about the possible political fallout from the scandal

Verb

club members were soon falling out about how to spend the money they'd made washing cars

I had planned to have a sports career, but things fell out otherwise.

Recent Examples on the Web

Noun

But many argue that the war has given the Iranians a better footing than originally anticipated, especially given the economic fallout globally. —Phillip M. Bailey, USA Today, 2 Apr. 2026

Trump’s shift represents his concern over the war’s economic fallout, Bloomberg argued, and his realization that events are no longer under his control. —Tom Chivers, semafor.com, 1 Apr. 2026

Verb

Your hair may fall out faster than before. —Kansas City Star, 27 Mar. 2026

White tie fell out of favor at the onset of World War I. —Vogue, 27 Mar. 2026

Word History

First Known Use

Noun

1946, in the meaning defined at sense 1a

Verb

15th century, in the meaning defined at sense 1

Phrases Containing fallout

• fallout shelter

Rhymes for fallout

• about
• bailout
• blackout
• blowout
• breakout
• burnout
• buyout
• checkout
• closeout
• cutout
• devout
• dropout

Kids Definition

fallout

1 of 2 noun

fall·​out ˈfȯ-ˌlau̇t 

: the often radioactive particles that are stirred up by or result from a nuclear explosion and descend through the atmosphere

fall out

2 of 2 verb

(ˈ)fȯ-ˈlau̇t

1

: to have a quarrel

2

: happen sense 1

Medical Definition

fallout

noun

fall·​out ˈfȯ-ˌlau̇t 

1

: the often radioactive particles stirred up by or resulting from a nuclear explosion and descending through the atmosphere

also : other polluting particles (as volcanic ash) descending likewise

2

: descent (as of fallout) through the atmosphere