A Yogi is a practitioner of Yoga. The word is also used to refer to ascetic practitioners of meditation in a number of South Asian religions including Hinduism, Buddhism, and Jainism.
Yoga (Sanskrit: योग) is a commonly known generic term for the physical, mental, and spiritual practices or disciplines which originated in ancient India with a view to attain a state of permanent peace. Specifically, yoga is one of the six āstika ("orthodox") schools of Hindu philosophy. One of the most detailed and thorough expositions on the subject is the Yoga Sūtras of Patañjali, which defines yoga as "the stilling of the changing states of the mind" (Sanskrit: योग: चित्त-वृत्ति निरोध:). Yoga has also been popularly defined as "union with the divine" in other contexts and traditions. Various traditions of yoga are found in Buddhism, Hinduism, Jainism and Sikhism.
Post-classical traditions consider Hiranyagarbha as the originator of yoga. Pre–philosophical speculations and diverse ascetic practices of first millennium BCE were systematized into a formal philosophy in early centuries CE by the Yoga Sutras of Patanjali. By the turn of the first millennium, Hatha yoga emerged as a prominent tradition of yoga distinct from Patanjali's Yoga Sutras and marks the development of asanas into the full body postures now in popular usage and, along with its many modern variations, is the style that many people associate with the word yoga today.