It's important to remember that "discipline" doesn't usually have an acronym like "RADAR" or "NASA".
However, if you are looking for a more descriptive phrase, here are some ways to express what "discipline" means:
* Training and instruction: This emphasizes the process of learning and developing skills.
* Self-control and order: This focuses on the ability to manage one's behavior and actions.
* A branch of knowledge: This refers to a specific field of study or practice, like "academic discipline" or "military discipline".
* Punishment or correction: This focuses on the negative aspects of discipline, like reprimands or sanctions.
Ultimately, the meaning of "discipline" depends on the specific context.