mainstay
🇺🇸
/ˈmeɪnsteɪ/
🇬🇧
/ˈmeɪnsteɪ/
The most important part of something that helps it exist or be successful.
Math is a mainstay of the school curriculum.
수학은 학교 커리큘럼의 중요한 핵심입니다.