* Παιδεία (Paideia): This is probably the closest overall translation. It encompasses education, training, and discipline, often in the sense of moral and intellectual development. It's a broader term than simply punishment or control.
* Αγωγή (Agōgē): This refers to training, leading, or guidance, often in a more practical sense than *paideia*. It could be used to describe the discipline involved in athletic training or military drill.
* Θεραπεία (Therapia): While primarily meaning "therapy" or "treatment," this could be used in the context of disciplined self-improvement or the disciplined application of a craft.
* Πειθαρχία (Peitharchia): This translates most literally to "obedience" or "submission to authority," and represents the aspect of discipline involving following rules and orders. This is a narrower meaning than the others.
* Έλεγχος (Elenchos): This word means "control" or "restraint" and could be used in the context of self-discipline or the discipline imposed by an external authority.
The best word to use will depend heavily on the specific context in which you're using the word "discipline."