outbreak
noun
out·break
ˈau̇t-ˌbrāk 
1
a
: a sudden or violent increase in activity or currency
the outbreak of war
b
: a sudden rise in the incidence of a disease
an outbreak of measles
c
: a sudden increase in numbers of a harmful organism and especially an insect within a particular area
an outbreak of locusts
2
Examples of outbreak in a Sentence
there was an immediate outbreak of paper shuffling and a pretense of work when the supervisor passed through the room
the government quelled the outbreak with ruthless efficiency
Recent Examples on the Web
The Polk County case is believed to stem from an ongoing outbreak in upstate South Carolina, which has seen 179 measles cases since July, according to the NC Department of Health and Human Services, the News & Observer reported.
—
Josh Shaffer, Charlotte Observer, 3 Jan. 2026
Iran is no stranger to nationwide protests, and the latest demonstrations have not come close to the last major outbreak in 2022, which was triggered by the death in police custody of Mahsa Amini, a young Iranian woman.
—CBS News, 2 Jan. 2026
Measles outbreaks in the US More than 2,000 measles cases were reported in the US in 2025 as ongoing outbreaks threaten elimination status.
—Alexandra Banner, CNN Money, 2 Jan. 2026
County officials argue the administration lacked the authority to claw back money appropriated by Congress, and that lawmakers intended the grants to strengthen long-term public health infrastructure and guard against future outbreaks, not expire when the COVID-19 emergency ended.
—Tracey McManus, Dallas Morning News, 2 Jan. 2026
See All Example Sentences for outbreak
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Josh Shaffer, Charlotte Observer, 3 Jan. 2026
Iran is no stranger to nationwide protests, and the latest demonstrations have not come close to the last major outbreak in 2022, which was triggered by the death in police custody of Mahsa Amini, a young Iranian woman.
—CBS News, 2 Jan. 2026
Measles outbreaks in the US More than 2,000 measles cases were reported in the US in 2025 as ongoing outbreaks threaten elimination status.
—Alexandra Banner, CNN Money, 2 Jan. 2026
County officials argue the administration lacked the authority to claw back money appropriated by Congress, and that lawmakers intended the grants to strengthen long-term public health infrastructure and guard against future outbreaks, not expire when the COVID-19 emergency ended.
—Tracey McManus, Dallas Morning News, 2 Jan. 2026
See All Example Sentences for outbreak
Cite this Entry
“Outbreak.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/outbreak. Accessed 8 Jan. 2026.
Copy CitationKids Definition
outbreak
noun
out·break
ˈau̇t-ˌbrāk
1
: a sudden increase in activity, use, or acceptance
the outbreak of war
2
: something (as an epidemic or revolution) that breaks out
an outbreak of measles
Medical Definition
outbreak
noun
out·break
ˈau̇t-ˌbrāk
1
: a sudden rise in the incidence of a disease
an outbreak of measles
2
: a sudden increase in numbers of a harmful organism and especially an insect within a particular area
an outbreak of locusts
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