proliferation

American  

[pruh-lif-uh-rey-shuhn] / prəˌlɪf əˈreɪ ʃən /

noun

1. the growth or production of cells by multiplication of parts.

2. a rapid and often excessive spread or increase.

   nuclear proliferation.

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proliferation British  

/ prəˌlɪfəˈreɪʃən /

noun

1. rapid growth or reproduction of new parts, cells, etc

2. rapid growth or increase in numbers

3. a great number

   done up in a proliferation of fancy frills

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Etymology

Origin of proliferation

First recorded in 1855–60; proliferate + -ion

Explanation

Proliferation is a rapid multiplication of parts or the increase in the number of something. Nuclear proliferation is a rapid increase of nuclear weapons. The proliferation of any living thing will often create an overpopulation problem and cause an environmental imbalance. A proliferation of fuzzy koala bears might seem kind of nice, but these cute little creatures would soon eat up all the eucalyptus, running out of food and causing problems for other species. We almost always use this word to describe stuff we don't want to increase rapidly. The excessive proliferation of mutated cells, for instance, is how cancer grows.

Example Sentences

Also distorting numbers are what’s called zero-hours contracts as well as the growing number of the self-employed, gig workers and the proliferation of internships, none of which are captured in official statistics.

From MarketWatch • Apr. 15, 2026

The rapid proliferation of drones has made many of those weapons less relevant, and spurred Ukrainian rag-tag arms producers to become global leaders in drone warfare and anti-drone systems.

From Barron's • Apr. 10, 2026

Government inaction is behind the proliferation in recent years of volunteer search “collectives,” many composed of relatives of the missing.

From Los Angeles Times • Apr. 6, 2026

The proliferation of offshore vehicles, combined with a laissez-faire attitude toward sources of foreign wealth, have made it an attractive place for well-to-do Iranians to park cash, real-estate experts and wealth managers say.

From The Wall Street Journal • Mar. 30, 2026

We have reached the point where proliferation of nuclear arms and resistance to nuclear disarmament threaten every person on the planet.

From "Cosmos" by Carl Sagan