纪律在英语中被称为discipline。来源：这个词来自拉丁文的"disciplina"，意思是训练或教导。

例句：

She needs to learn discipline in order to succeed. (她需要学习纪律来成功。)

The military is known for its discipline. (军队以其纪律而闻名。)

We need to maintain discipline in the classroom. (我们需要在教室里保持纪律。)