Disciplinary means relating to discipline, rules, or punishment for breaking them. When a student breaks school rules, they might face disciplinary action, such as detention or losing recess privileges. When a soccer player commits too many fouls, the referee takes disciplinary measures, like issuing a yellow card or ejecting them from the game.

The word often appears in formal contexts. A company might hold a disciplinary hearing when an employee violates workplace rules. Schools have disciplinary codes that spell out what happens when students misbehave. The military uses disciplinary procedures to maintain order and accountability.

But disciplinary doesn't always mean punishment. It can simply refer to a particular field of study or practice. Scientists talk about working across disciplinary boundaries when biologists and chemists collaborate on a project. A disciplinary expert is someone who has deep knowledge in their specific field. When colleges organize their courses by subject, like history or mathematics, they're creating disciplinary divisions.