critical mass

English Thesaurus

1. the minimum mass of fissionable material that can sustain a chain reaction (noun.attribute)

hypernym	:	mass,
definition	:	the property of a body that causes it to have weight in a gravitational field (noun.attribute)

2. the minimum amount (of something) required to start or maintain a venture (noun.attribute)

hypernym	:	amount,
definition	:	the relative magnitude of something with reference to a criterion (noun.attribute)