Definition of "critical mass" []

• The smallest mass of a fissionable material that will sustain a nuclear chain reaction at a constant level. (noun)
• The amount of matter needed to generate sufficient gravitational force to halt the current expansion of the universe. (noun)
• An amount or level needed for a specific result or new action to occur: "The sudden national uproar over drugs and drug abuse has reached politically critical mass in Washington” ( Tom Morganthau). (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Factors which act to slow the rate of adoption of an interactive innovation before the critical mass is reached (like network externali ties), then serve to speed up the adoption rate after the critical mass is attained (Wieber, 1992, 1995)."
• "Shermesh and Tellis 2002 determined the year in which the critical mass occurred by inspecting their data on the annual rate of adoption for each new product."
• "Marketing diffusion scholars have pioneered in identifying a new dependent variable for their analyses, the amount of time required to reach critical mass for a new product in a nation this variable is called “time-to-take-off”."