The word 'discipline' is derived from the Latin word 'disciplina' which means training. It is the training of the mind and the moral faculties. When the mental and moral qualities are exercised in some regular way, they get training and become discipline.

The mental and moral faculties are manifested in some external form. For example, a mentally disciplined man learns how to think in a systematic way in an orderly manner. The moral faculties can be said to have training if they show themselves up in the right rules of conduct. So, a man who is disciplined mentally will not think in a disorderly way. His thoughts will be expressed in a systematic way. A morally trained man will not act in a way which is not approved by his society or his religion or moral ideal. Some may also confuse discipline with punishment. But they are not the same thing.

Punishment may be regarded as a means towards the achievement of discipline. Real discipline should be such that one accepts it without any fear or punishment, accepts it of his own free will, out of his own liking for it. Discipline is required at every sphere of existence from the universe down to every form of life.