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

That’s because a critical mass of people must be vaccinated in order to attain herd immunity.

From Outside Online

Pence’s display of leadership means something, but not nearly as much as implementing a plan so a critical mass of people can get immunized — ending the coronavirus nightmare he and his boss have actively made worse.

From Vox

So there’s a critical mass in the state — particularly in the northeast of the state, but really throughout the state — that just aren’t taking the precautions they should be taking.

From Vox

They would rather, perhaps, become the next WhatsApp and be a 2BN user silo rather than play nice with other people because they’re already past critical mass.

From TechCrunch

If it is, it will take Apple longer to get to some sort of “critical mass.”

From Search Engine Land

Without a critical mass of media, the politicians can get away with claiming the Atlanta paper has a vendetta against them.

From The Daily Beast

If a critical mass of people is afraid or is convinced to fear, the signal is contagious.

From The Daily Beast

A critical mass of influential figures now demands the GOP act on immigration, one way or the other.

From The Daily Beast

And awareness is the first step in the process of building a critical mass to effectuate change on issues.

From The Daily Beast

With Seacrest, the queue of big-name Miss Havishams in lacy, "nude" boring dresses reached a critical mass.

From The Daily Beast

Too well shielded for the blast to get them, but the heat melted the fissionables down to critical mass.

From Project Gutenberg

Claire always knew what to do when his temper started climbing to critical mass.

From Project Gutenberg

If only they had a tube of some sort that would withstand the chemical explosion—the one that brought the critical mass together!

From Project Gutenberg

First, two or more pieces of plutonium large enough to form a critical mass.

From Project Gutenberg

Finally, at perhaps a hundred thousand times critical mass, and still in perfect sync, the Vangs all went off.

From Project Gutenberg