[ krit-i-kuhl mas ]
/ ˈkrɪt ɪ kəl ˈmæs /
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.
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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Origin of critical mass
First recorded in 1940–45
Words nearby critical mass
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2020
British Dictionary definitions for critical mass
the minimum mass of fissionable material that can sustain a nuclear chain reaction
the minimum amount of money or number of people required to start or sustain an operation, business, process, etcthe critical mass for a subscription digital sports channel
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Scientific definitions for critical mass
The smallest mass of a fissionable material that will sustain a nuclear chain reaction.
The amount of matter needed to generate sufficient gravitational force to halt the current expansion of the universe. See also big bang big crunch.
The American Heritage® Science Dictionary Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
Cultural definitions for critical mass
notes for critical mass
The term critical mass is used to refer generally to the minimum amount of something needed to produce a given effect: “The town needs a critical mass of industry to attract more business.”
The New Dictionary of Cultural Literacy, Third Edition Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.