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

For investors, the framing that applies here is the one used for cybersecurity a decade ago, when the proliferation of connected devices made security spending nondiscretionary.

From MarketWatch • Apr. 13, 2026

The proliferation of shell companies in Hong Kong is so troublesome that U.S. authorities began in October to target the addresses of businesses that handle the paperwork of establishing a company.

From The Wall Street Journal • Apr. 11, 2026

But Germany's government persuaded Siemens to withdraw over concerns about nuclear proliferation.

From Barron's • Apr. 4, 2026

The seemingly limitless proliferation of cases in which lawyers have been caught letting fictitious AI-generated legal citations contaminate their briefs continues to amaze.

From Los Angeles Times • Mar. 27, 2026

What happens in a cell to change its orderly multiplication into the wild and uncontrolled proliferation of cancer?

From "Silent Spring" by Rachel Carson