Yoga as exercise is a physical activity consisting mainly of postures, often connected by flowing sequences, sometimes accompanied by breathing exercises, and frequently ending with relaxation lying down or meditation. Yoga in this form has become familiar across the world, especially in the US and Europe. It is derived from medieval Haṭha yoga, which made use of similar postures, but it is generally simply called "yoga". Academics have given yoga as exercise a variety of names, including modern postural yoga[1][a] and transnational anglophone yoga.[3] Posture is described in the Yoga Sutras II.29 as the third of the eight limbs, the ashtanga, of yoga. Sutra II.46 defines it as that which is steady and comfortable, but no further elaboration or list of postures is given.