In Sanskrit yoga means “union”. People often confuse Yoga and Yogasana, yogasana is the set of physical postures whereas Yoga means being in union with the cosmos. Yoga was first developed by Adishvara Shiva, also called as Aadhi Yogi (or the first yogi).
The yogasanas or the postures is one of the 8 limbs of yoga. However the western world has classified Yogasanas as a type of non-aerobic exercise that combines precise body postures, breathing techniques and meditation. However in the traditional Indian system, Yoga is often described as an Inner Science.