from The American Heritage® Dictionary of the English Language, 4th Edition
- n. The smallest mass of a fissionable material that will sustain a nuclear chain reaction at a constant level.
- n. The amount of matter needed to generate sufficient gravitational force to halt the current expansion of the universe.
- n. 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).
from Wiktionary, Creative Commons Attribution/Share-Alike License
- n. the amount of fissile material that is needed to support a self-sustaining nuclear chain reaction
- n. A quantity or amount required to trigger a phenomenon.
from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.
- n. the minimum mass of fissionable material that can sustain a chain reaction
- n. the minimum amount (of something) required to start or maintain a venture
Sorry, no etymologies found.