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
As a result of the outbreak, crew members aboard the ship consulted with the CDC’s Vessel Sanitation Program regarding proper cleaning procedures and reporting cases.
—
Natalia Senanayake, PEOPLE, 6 Dec. 2025
The actions since late summer will leave the country less prepared for the next measles outbreak, foodborne illness cluster, maternal mortality crisis, or emerging pandemic.
—Dr. Debra Houry, Time, 5 Dec. 2025
As vaccine rates drop, illness does return, Hennessy said, exemplified by the nation's ongoing measles outbreak.
—Madeline Heim, jsonline.com, 5 Dec. 2025
The illness caused 15 of 18 total outbreaks in 2024, and 13 out of 14 the prior year.
—Nathan Diller, USA Today, 5 Dec. 2025
See All Example Sentences for outbreak
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Natalia Senanayake, PEOPLE, 6 Dec. 2025
The actions since late summer will leave the country less prepared for the next measles outbreak, foodborne illness cluster, maternal mortality crisis, or emerging pandemic.
—Dr. Debra Houry, Time, 5 Dec. 2025
As vaccine rates drop, illness does return, Hennessy said, exemplified by the nation's ongoing measles outbreak.
—Madeline Heim, jsonline.com, 5 Dec. 2025
The illness caused 15 of 18 total outbreaks in 2024, and 13 out of 14 the prior year.
—Nathan Diller, USA Today, 5 Dec. 2025
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 Dec. 2025.
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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