critical mass

[krit-i-kuhl mas]

noun

1. Physics.,  the amount of a given fissionable material necessary to sustain a chain reaction at a constant rate.

   The critical mass for a bomb based on uranium fission is different than that for plutonium fission.

2. an amount necessary or sufficient to have a significant effect or to achieve a result.

   a critical mass of popular support.

critical mass

noun

1. the minimum mass of fissionable material that can sustain a nuclear chain reaction

2. the minimum amount of money or number of people required to start or sustain an operation, business, process, etc

   the critical mass for a subscription digital sports channel

Word History and Origins

Origin of critical mass¹

First recorded in 1940–45

Example Sentences

The Epstein saga, which seemed to be old news at the beginning of this year, is approaching a self-sustaining critical mass that will be difficult for anyone, no matter how well-connected or influential, to contain.

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For two years, labor organizers tried to unionize employees at a trio of celebrated California national parks, but they couldn’t reach critical mass.

Read more on Los Angeles Times

"There is a critical mass of employment," he explains.

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This is crucial if America’s nonviolent anti-MAGA movement is to reach critical mass.

Read more on Salon

"I think it could do quite a lot of damage to Labour and the Greens if it gets above a critical mass," he said.

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