supplementary
🇺🇸
/ˌsʌplɪˈmentri/
🇬🇧
/ˌsʌplɪˈmentri/
extra, added to make something better or complete
The teacher gave us supplementary materials to help us understand the lesson better.
선생님이 수업을 더 잘 이해할 수 있도록 보충 자료를 주셨어요.