Sanskrit `union'. Hindu philosophical system attributed to Patanjali, who lived about 150 BC at Gonda, Uttar Pradesh, India. He preached mystical union with a personal deity through the practice of self-hypnosis and a rising above the senses by abstract meditation, adoption of special postures, and ascetic practices. As practised in the West, yoga is more a system of mental and physical exercise, and of induced relaxation as a means of relieving stress.