[ U ] training that produces obedience or self-control, often in the form of rules and punishments if these are broken, or the obedience or self-control produced by this training:

[ U ] Discipline is also the ability to control a mental activity:

[ C ] a particular area of study, esp. a subject studied at a college or university:

to punish someone:

[ U ] the practice of making sure that people obey rules and do not cause problems:

[ U ] also self-discipline the ability to make yourself do something, even if it is difficult, so that you can achieve a goal:

[ C ] a subject or a particular type of work:

HR to deal with a worker who does not obey company rules, for example by giving them a written warning:

to carefully control the way that you work, live, or behave, especially to achieve a goal: