containment

American  

[kuhn-teyn-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

It’s been just four days since firefighters reached 100% containment of the 18,379-acre blaze that scorched about one-third of the island and damaged many prized resources, including the island’s rare Torrey pines.

From Los Angeles Times • Jun. 10, 2026

Other measures include establishing a containment zone around the site of the first US infection along the southern US border, and using sniffer dogs to detect the insects.

From BBC • Jun. 5, 2026

She hurried back as the fires broke containment, but her absence, which her social media posts seemed to obscure, became the symbol of a disorganized response to the disaster.

From Slate • Jun. 3, 2026

NAIROBI, Kenya—The fast-spreading Ebola virus is overwhelming creaking hospitals and clinics in the Democratic Republic of Congo, dimming hopes for quick containment of what is already the third-largest outbreak of the killer disease in history.

From The Wall Street Journal • May 24, 2026

In an emergency, the containment should trap gases that might escape from the inner chambers, but we rely on the reactor vessel to keep a nuclear reaction—and the radiation it produces—contained.

From "Meltdown" by Deirdre Langeland

Related Words

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