English Reference
noun

containment

n.
US /kənˈteɪnmənt/ UK /kəntˈeɪnmənt/ con·tain·ment UK spelling containment's, containment's

  1. 01 B2 Upper Intermediate

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

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

    Simple

    The government's main goal was the containment of the virus to a single city.

    In context

    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. 02 C1 Advanced Technical Science

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

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

    Simple

    Engineers checked the steel containment building for any signs of damage.

    In context

    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. 03 C1 Advanced Academic

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

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

    Simple

    The policy of containment was designed to stop the spread of communism.

    In context

    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. 04 C2 Proficiency Technical Math

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

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

    Simple

    The teacher explained the containment of the set of even numbers within the set of integers.

    In context

    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.

Virus spreading in DRC faster than containment efforts.

Al Jazeera· 15 Aug 2026

The CAA's Nicholson says "the most important thing is to bung it in water and cool it down," though some airlines did use specialised containment devices.

BBC News· 6 Aug 2026

From contain + -ment.

Etymology adapted from Wiktionary, available under CC BY-SA 4.0.

This entry
Level C1 · Advanced
Frequency Frequent
Updated