What is commonly referred to as "yoga" can be more accurately described by the Sanskrit word asana, which refers to the practice of physical postures or poses.
Asana is only one of the eight "limbs" of yoga, the majority of which are more concerned with mental and spiritual well being than physical activity. In the West, however, the words asana and yoga are often used interchangeably.
Major branches of yoga in Hindu philosophy include Rāja Yoga, Karma Yoga, Jnana Yoga, Bhakti Yoga, and Hatha Yoga.According to the authoritative Indian philosopher Sarvepalli Radhakrishnan, yoga, based on the Yoga Sutras of Patanjali, comprises one of the six main Hindu schools of philosophy (darshanas), together with Kapila's Samkhya, Gautama's Nyaya, Kanada's Vaisheshika, Jaimini's Purva Mimamsa, and Badarayana's Uttara Mimamsa or Vedanta. Many other Hindu texts discuss aspects of yoga, including the Upanishads, the Bhagavad Gita, the Hatha Yoga Pradipika, the Shiva Samhita and various Tantras.