The Sanskrit word 'Yoga' has two meaning, because it is derived from two roots - one is 'yujir yoge' and other is 'yuj samadhou'. The root 'yujir yoge' means to join or to unite. Religious leaders accept this meaning because their philosophy is based on dualism. They always try to project an external God and become Gog's representitives. By this they rule over their followers.However the other root 'yuj samadhou' means to concentrate. Patanjali tried to preach that Yoga where mind is concentrate.