Yoga is derived from the Sanskrit word - Yuj which means union or joining.
Literally, Yoga is one of the six systems of Indian philosophies which are composed by Maharishi Patanjali in-between 200-300 BC. Yoga is the science of life and an ideal way of living to achieve total health, peace and harmony. Ultimate goal of yoga is to achieve total health and a state of harmony between mind and body.
Modern development of yoga has less of eternal approach and focused more on physical aspects, therapeutic values and self development. At present Hatha Yoga is the most common form of yoga which is being practiced all over the world.
Patanjali's yoga is considered as classical and traditional yoga which is also most authentic and systematic form of yoga science. Patanjali has classified 8 limbs of yoga which is popularized as Astang Yoga.