臨りん界かい量りょう

noun

critical mass

Technical term in physics and nuclear engineering; also used figuratively for the point at which something becomes self-sustaining.

• 核かく分ぶん裂れつを維い持じするには臨りん界かい量りょうが必ひつ要ようだ。

  A critical mass is necessary to sustain nuclear fission.

• その運うん動どうは臨りん界かい量りょうに達たっして急きゅう速そくに広ひろまった。

  The movement reached critical mass and spread rapidly.