臨界量

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

(2)連鎖反応を継続することができる核分裂性物質の最小限の質量

(3)the minimum amount (of something) required to start or maintain a venture; "the battle for the computer market has now reached critical mass"; "there is now a critical mass of successful women to take the lead"; "they sold the business because it lacked critical mass"

(4)ベンチャーを始めるか維持するのに必要な最小の量（何かの）

(1)