Āsana means seat. Patañjali says only that the posture should be steady and easy, so that the body no longer disturbs meditation. The haṭha yoga texts of the medieval period developed many postures for strengthening and purifying the body, and these became the basis of modern postural yoga.
Āsana
Posture: in classical yoga, a seat that is steady and comfortable; in haṭha yoga, the many bodily postures.
Also: Asana, posture