名詞 criticality:

1. a state of critical urgency
   同義詞：criticalness, cruciality
2. a critical state; especially the point at which a nuclear reaction is self-sustaining

crit.i.cal.i.ty

n.（名詞）
The quality, state, or degree of being of the highest importance:
臨界狀態(tài)：接近頂尖重要的性質(zhì)、狀態(tài)或程度：
例句：
.The challenge of our future food supply is approaching criticality.(New York Times)
.我們未來食物供應的挑戰(zhàn)已接近臨界狀態(tài).(紐約時報)

Physics The point at which a nuclear reaction is self-sustaining.
【物理學】 臨界點：核反應能夠自我維持的一個點