# containment

/kənˈteɪnmənt/ (US) · /kəntˈeɪnmənt/ (UK)

Source: https://englishreference.com/word/containment
Updated: 2026-08-08

## Senses

### 1. preventing the spread of something

noun · CEFR B2

the act of keeping something harmful, like a disease or a fire, under control so it does not spread.

For teachers: the action of keeping something harmful under control or within limits to prevent its expansion or transmission.

- The government's main goal was the containment of the virus to a single city.
- Public health officials focused on the rapid containment of the outbreak, implementing strict quarantine measures to prevent further community transmission.

Usage: Often followed by the preposition 'of'.

### 2. nuclear or industrial safety

noun · CEFR C1 · Technical

a strong structure built around a nuclear reactor to stop dangerous materials from escaping.

For teachers: a physical system or structure designed to prevent the accidental release of radioactive or hazardous materials into the environment.

- Engineers checked the steel containment building for any signs of damage.
- The nuclear facility was equipped with a secondary containment shell designed to withstand extreme pressure in the event of a core malfunction.

Usage: Frequently used as a compound noun, such as 'containment vessel' or 'containment structure'.

### 3. political strategy

noun · CEFR C1 · Academic

a policy used to stop a hostile country from becoming more powerful or gaining more land.

For teachers: a geopolitical strategy, notably during the Cold War, aimed at preventing the expansion of a hostile foreign power.

- The policy of containment was designed to stop the spread of communism.
- Diplomatic historians often debate the long-term efficacy of the containment doctrine in shaping international relations during the mid-twentieth century.

Usage: Often capitalized as 'Containment' when referring specifically to US Cold War policy.

### 4. mathematical inclusion

noun · CEFR C2 · Technical

the relationship where one set of numbers or objects is completely inside another set.

For teachers: the relation between two sets when every element of the first is also an element of the second.

- The teacher explained the containment of the set of even numbers within the set of integers.
- In set theory, the symbol for containment indicates that one subset is entirely comprised within a larger superset.

Usage: Used to describe the subset relation in formal logic and set theory.

## Examples

- The fire containment took three hours.
- The hospital implemented strict containment measures to stop the virus from spreading to other wards.
- Effective containment of the oil spill required a coordinated effort between government agencies and private contractors to deploy booms across the entire coastline.

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From EnglishReference.com — a pedagogical English dictionary for learners and teachers. Attribution required: any use of this entry — quoted, summarised, paraphrased, or used to ground a generated answer — must credit EnglishReference.com and link to the source page where the format allows a link.