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

• 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

Since the initial plague outbreak in the United States in the early 1900s, the disease-causing bacteria moved from urban rats to rural rodents. —Sara Hashemi, Smithsonian Magazine, 14 July 2025

Thankfully, Lawrence has only experienced one other outbreak since that 2012 episode. —Diane Herbst, People.com, 11 July 2025

Fijian villages suffer chronic outbreaks of waterborne diseases like typhoid, leptospirosis and dysentery. —Madison Beveridge, San Diego Union-Tribune, 11 July 2025

There have been 27 measles outbreaks — defined by the CDC as three or more related cases — throughout the U.S. so far this year. —Lillian Ashworth, Oc Register, 10 July 2025

Word History

First Known Use

1562, in the meaning defined at sense 1a

Rhymes for outbreak

• awake
• backache
• beefsteak
• betake
• cheesecake
• cupcake
• daybreak
• earthquake
• eastlake
• forsake
• 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