juvenile lead
noun [ C ] uk/ˌdʒuː.vən.aɪl ˈliːd/ us/ˌdʒuː.vən.nəl ˈliːd/
年轻主角（戏剧和电影中年轻演员扮演的最重要角色）
the most important part that is performed by a young actor in a play or film
Rachael is playing the juvenile lead in the Christmas show. 雷切尔在圣诞表演中扮演女主角。