The word “Yoga” essentially means, “that which brings you to reality”. Literally, it means “union.” Union means it brings you to the ultimate reality, where individual manifestations of life are surface bubbles in the process of creation. Right now, a coconut tree and a mango tree have popped up from the same earth. From the same earth, the human body and so many creatures have popped up. It is all the same earth.
Yoga means to move towards an experiential reality where one knows the ultimate nature of the existence, the way it is made.
Ramdev is best yoga teacher.