The earliest references to hatha yoga are in Buddhist works dating from the eighth century. The earliest definition of hatha yoga is found in the 11th century Buddhist text Vimalaprabha, which defines it in relation to the center channel, bindu etc. Hatha yoga synthesizes elements of Patanjali's Yoga Sutras with posture and breathing exercises. It marks the development of asanas (plural) 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.
^ For instance, Kamalashila (2003), p. 4, states that Buddhist meditation "includes any method of meditation that has Enlightenment as its ultimate aim." Likewise, Bodhi (1999) writes: "To arrive at the experiential realization of the truths it is necessary to take up the practice of meditation.... At the climax of such contemplation the mental eye … shifts its focus to the unconditioned state, Nibbana...." A similar although in some ways slightly broader definition is provided by Fischer-Schreiber et al. (1991), p. 142: "Meditation – general term for a multitude of religious practices, often quite different in method, but all having the same goal: to bring the consciousness of the practitioner to a state in which he can come to an experience of 'awakening,' 'liberation,' 'enlightenment.'" Kamalashila (2003) further allows that some Buddhist meditations are "of a more preparatory nature" (p. 4).
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^ "application or concentration of the thoughts, abstract contemplation, meditation , (esp.) self-concentration, abstract meditation and mental abstraction practised as a system (as taught by Patañjali and called the yoga philosophy; it is the second of the two sāṃkhya systems, its chief aim being to teach the means by which the human spirit may attain complete union with īśvara or the Supreme Spirit; in the practice of self-concentration it is closely connected with Buddhism". Monier-Williams, A Sanskrit Dictionary (1899)