Discipline is the practice of making people obey rules or standards of behaviour, and punishing them when they do not.

Discipline is the quality of being able to behave and work in a controlled way which involves obeying particular rules or standards.

If you refer to an activity or situation as a discipline, you mean that, in order to be successful in it, you need to behave in a strictly controlled way and obey particular rules or standards.

If someone is disciplined for something that they have done wrong, they are punished for it.

If you discipline yourself to do something, you train yourself to behave and work in a strictly controlled and regular way.

A discipline is a particular area of study, especially a subject of study in a college or university.