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

: insurrection, revolt

Synonyms of outbreak

• flurry
• burst
• outburst

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

That’s poised to exceed the 2,288 cases in all of 2025, which was the worst outbreak since 1991. — Business Columnist, Los Angeles Times, 3 July 2026

Recurring outbreaks were common in places where sanitation was poor, historians confirm. — Melissa Rudy, FOXNews.com, 3 July 2026

That is far smaller than the 2025 outbreak that killed millions of commercial poultry. — Ryan Brennan, Miami Herald, 2 July 2026

There were 23 outbreaks that met that threshold in 2025, 18 of which were caused by norovirus, and the illness was behind 15 out of 18 outbreaks the prior year. — Nathan Diller, USA Today, 2 July 2026

Word History

First Known Use

1562, in the meaning defined at sense 1a

Rhymes for outbreak

• awake
• backache
• beefsteak
• betake
• cheesecake
• cupcake
• daybreak
• earthquake
• forsake
• gouache
• handshake
• headache

Kids 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