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
In natural systems, pests seldom reach outbreak levels because predators, parasitoids, and disease organisms (collectively called natural enemies) keep populations in check.
—
Kim Toscano, Southern Living, 5 Apr. 2026
More than 180 ships have successfully transited the strait since the outbreak of the conflict, according to Iran’s semi-official Tasnim news agency.
—Billy Stockwell, CNN Money, 5 Apr. 2026
Drops in vaccinations have already contributed to the rapid resurgence of measles outbreaks across the country.
—Eduardo Cuevas, USA Today, 4 Apr. 2026
The outbreak of war with Iran is leading to a big price increase for urea from the Middle East.
—Alan Gionet, CBS News, 3 Apr. 2026
See All Example Sentences for outbreak
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Kim Toscano, Southern Living, 5 Apr. 2026
More than 180 ships have successfully transited the strait since the outbreak of the conflict, according to Iran’s semi-official Tasnim news agency.
—Billy Stockwell, CNN Money, 5 Apr. 2026
Drops in vaccinations have already contributed to the rapid resurgence of measles outbreaks across the country.
—Eduardo Cuevas, USA Today, 4 Apr. 2026
The outbreak of war with Iran is leading to a big price increase for urea from the Middle East.
—Alan Gionet, CBS News, 3 Apr. 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 6 Apr. 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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