1 [U] the practice of training people to obey rules and behave well 纪律: A good teacher must be able to maintain discipline in the classroom. 好的老师必须能维持课堂的纪律。

2 [U] the practice of training your mind and body so that you control your actions and obey rules; a way of doing this 训练，磨练（使更能控制自己的行动并且遵守规则）；训练或磨练方法: It takes a lot of self-discipline to study for three hours a day. 每天温习三小时需要很强的自律精神。 Having to get up early every day is good discipline for a child. 每天得早起对孩子来说是很好的锻炼。

3 [C] a subject of study; a type of sporting event 学科；体育项目: Barry's a good all-round athlete, but the long jump is his strongest discipline. 巴里是一名出色的全能运动员，但跳远是他最强的一项。