[U] a way of training someone so that they learn to control their behaviour and obey rules

训练，管教:

The book gives parents advice on discipline.

这本书向父母提供了管教方面的建议。

serious discipline problems in the police force

警察队伍内严重的纪律问题

[U] the ability to control your own behaviour, so that you do what you are expected to do

自制力:

Working from home requires a good deal of discipline.

在家上班要具备良好的自制力。

[C,U] a way of training your mind or learning to control your behaviour

〔思想或行为的〕纪律，训练:

Martial arts teach respect, discipline, and cooperation.

武术能教人尊敬他人、遵守纪律并且相互合作。

Learning poetry is a good discipline for the memory.

背诗是训练记忆力的一种好方法。

[C] an area of knowledge or teaching, especially one such as history, chemistry, mathematics etc that is studied at a university

〔尤指大学的〕专业，科目

to punish someone in order to keep order and control

惩处〔某人〕:

The officers were later disciplined.

那些官员后来受到了处罚。

to teach someone to obey rules and control their behaviour

训练，管教:

Different cultures have different ways of disciplining their children.

不同的文化有不同的管教儿童的方法。

discipline yourself (to do sth), to control the way you work, how regularly you do something etc, because you know it is good for you

严格要求自己，约束自己（去做某事）:

Try to discipline yourself to write every day.

要想办法约束自己每天写作。