mainspring
🇺🇸
/ˈmeɪnsprɪŋ/
🇬🇧
/ˈmeɪnsprɪŋ/
The key element or driving force behind something.
Her passion for helping others is the mainspring of her charitable work.
他の人を助けることへの情熱が彼女の慈善活動の原動力です。
The central spring in a clock or watch that provides the power to keep it running.
The watchmaker carefully replaced the worn-out mainspring in the antique timepiece.
時計職人は慎重に時代遅れの時計の摩耗した主発条を交換しました。