Meaning of “discipline” - Learner’s Dictionary

discipline

noun uk us /ˈdɪsəplɪn/
CONTROL [ U ]

B2 the control of people's behaviour using rules and punishments:

There should be better discipline in schools.
SELF CONTROL [ U ]

the ability to control your own behaviour carefully:

I don't have enough discipline to save money.
KNOWLEDGE [ C ] formal

a particular subject of study:

the scientific disciplines
→ See also self-discipline

(Definition of “discipline noun” from the Cambridge Learner’s Dictionary © Cambridge University Press)