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

As fallout from the war with Iran keeps fuel prices high, few states are making moves to suspend their gas and diesel taxes. —Kathryn Watson, CBS News, 16 Apr. 2026

The owners of the bathhouse, known as Watergarden, blamed the economic fallout from the COVID-19 pandemic for the demise of the venue after 43 years of operation as a men’s health club. —George Avalos, Mercury News, 15 Apr. 2026

Verb

So, in a general process of professionalization that changed the way that music was experienced, raising standards while widening the gap between expert and amateur, the mandolin fell out of fashion. —Tim Parks, New Yorker, 11 Apr. 2026

Police, however, didn't question him about any physical or forensic evidence found, rather focusing on what the couple was doing in the Bahamas and what happened in the hours prior to Lynette falling out of the dinghy. —Adam Sabes , Peter D'abrosca, FOXNews.com, 11 Apr. 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