English Reference
noun

proliferation

n.
US /ˌpɹoʊɫɪfɝˈeɪʃən/ UK /pɹəlˌɪfəɹˈeɪʃən/ pro·lif·er·a·tion UK spelling proliferations

  1. 01 C1 Advanced Academic

    a sudden and fast increase in the number or amount of something.

    the rapid and often excessive spread or increase in the number of something. Uncountable in its general sense, though often used with 'of'.

    Simple

    The proliferation of smartphones has changed how we communicate every day.

    In context

    The rapid proliferation of digital streaming platforms has fundamentally altered the economic landscape of the entertainment industry.

    Usage

    Often followed by the preposition 'of'.

  2. 02 C2 Proficiency Technical Medicine

    the fast growth of cells or parts of a living thing.

    the reproduction or multiplication of similar forms, especially cells or organelles. Typically used in medical or biological contexts.

    Simple

    The medicine is designed to stop the proliferation of cancer cells.

    In context

    Abnormal cell proliferation is a primary characteristic of many malignant tumours, requiring targeted therapeutic intervention.

    Usage

    Commonly used as an uncountable noun in scientific literature.

  3. 03 C1 Advanced Formal

    the spread of nuclear weapons to countries that do not have them.

    the spread of nuclear weapons, fissionable material, and weapons-applicable nuclear technology and information to nations not recognized as 'Nuclear Weapon States'.

    Simple

    Many world leaders are worried about the proliferation of nuclear weapons.

    In context

    International treaties were established to prevent the proliferation of atomic weaponry and to encourage the peaceful use of nuclear energy.

    Teacher's tip

    In political contexts, you will almost always see this paired with 'non-' (non-proliferation) to describe efforts to stop the spread.

    disarmamentnon proliferation

Despite the proliferation of psychobabble and therapy-speak, there’s also some good science.

The Guardian· 12 Aug 2026

But it was hard to control the proliferation of cheaply produced battery packs from East Asia, as well as vapes and other powered devices, with questionable quality controls.

BBC News· 6 Aug 2026

Borrowed from French prolifération.

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

This entry
Level C1 · Advanced
Frequency Frequent
Updated