critical mass

American  

[krit-i-kuhl mas] / ˈkrɪt ɪ kəl ˈmæs /

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.

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critical mass British  

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

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Etymology

Origin of critical mass

First recorded in 1940–45

Example Sentences

“There are clearly a lot of unknowns in how this all plays out, but there is clear risk to returns as AVs hit critical mass,” the analysts added.

From Barron's

“There are clearly a lot of unknowns in how this all plays out, but there is clear risk to returns as AVs hit critical mass,” the analysts added.

From Barron's

"And therefore, because there's no critical mass, they are really not part of the core of this small start-up village. And therefore, in my opinion we need to create critical mass."

From BBC

That will change when automation reaches critical mass.

From The Wall Street Journal

With such fragmentation, it’s much harder for a negative storyline to reach critical mass.

From Los Angeles Times