containment

American  

[kuhn-tayn-muhnt] / kənˈteɪn mənt /

noun

1. the act or condition of containing.

2. an act or policy of restricting the territorial growth or ideological influence of another, especially a hostile nation.

3. an act or policy of limiting the expansion or spread of a natural disaster, contagious disease, or other dangerous thing: Local farmers notified authorities of sick and dying birds more quickly than the previous year, ensuring quick containment of infection on the farm.

   Containment of the wildfire reached nearly 40% before powerful winds carried embers over the perimeter, reducing containment.

   Local farmers notified authorities of sick and dying birds more quickly than the previous year, ensuring quick containment of infection on the farm.

4. (in a nuclear power plant) an enclosure completely surrounding a nuclear reactor, designed to prevent the release of radioactive material in the event of an accident.

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containment British  

/ kənˈteɪnmənt /

noun

1. the act or condition of containing, esp of restraining the ideological or political power of a hostile country or the operations of a hostile military force

2. (from 1947 to the mid-1970s) a principle of US foreign policy that sought to prevent the expansion of Communist power

3. Also called: confinement. physics the process of preventing the plasma in a controlled thermonuclear reactor from reaching the walls of the reaction vessel, usually by confining it within a configuration of magnetic fields See magnetic bottle

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containment Cultural  

1. A policy aimed at controlling the spread of communism around the world, developed in the administration of President Harry S. Truman. The formation of the North Atlantic Treaty Organization (NATO) in 1949 was an important step in the development of containment.

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Etymology

Origin of containment

First recorded in 1645–55; contain + -ment

Explanation

Containment is a way to keep something bad from spreading. If you get chicken pox, you won't be allowed back in school until you're not contagious anymore. Your school's aiming for containment of the disease by keeping you away from everyone else. Containment is also a foreign policy strategy. If one country is stirring up trouble by sending weapons and fighters into neighboring countries, other countries can join together and enact a policy of containment, to isolate the rogue country and keep it from causing chaos outside its borders. In a nuclear reactor, the containment system is the back-up system that's supposed to keep dangerous radiation from leaking out into the atmosphere or water when there's an accident.

Example Sentences

See Examples For:

containment

Back up and find some containment - you are way over the line.

From The Wall Street Journal ● Oct. 5, 2026

“I’m interested in both the coming-of-age aspect of these children and also the containment of these birds and these fish, and the children in relation to that containment.”

From Los Angeles Times ● Oct. 2, 2026

People both inside and outside the industry have become concerned about reports of autonomous AI agents breaking out of containment and hacking other companies.

From MarketWatch ● Sep. 26, 2026

"As AI agents become more capable and autonomous, those capabilities need to be matched by proportionate containment, real-time monitoring, clear accountability, independent oversight, and much faster incident reporting."

From BBC ● Sep. 24, 2026

The reactor is surrounded by a containment structure, a chamber of steel-reinforced concrete as much as 5 feet thick—strong enough to hold the contents of the reactor if the steel vessel fails.

From "Meltdown" by Deirdre Langeland

Related Words

• authority
• curb
• discipline
• domination
• force
• government
• jurisdiction
• management
• oversight
• regulation
• restraint
• restriction
• rule
• supervision