“[Moral] restraint,” or “discipline,” the second rung in the ladder of the Ashtanga Yoga (eight-limbed yoga) taught by Patanjali in the Yoga Sutras. It involves five guidelines regarding the interaction with the “inner world”: saucha (purity), santosha (contentment), tapas (asceticism), svadhyaya (spiritual study), and ishvarapranidhana (devotion to the Lord). Read more about the niyama here.