noun
condensation nucleus
Technical term in meteorology for a particle that serves as a surface for water vapor to condense upon, forming cloud droplets.
雲ができるには、大気中に凝結核が必要です。
Condensation nuclei in the atmosphere are necessary for clouds to form.
Compound of 凝結 (gyōketsu, 'condensation') and 核 (kaku, 'nucleus').