Sanatana Yoga means the Eternal truth or Divine Union-Yoga that existed before creation, during existence and that will still exist after all matter has ceased to exist.
"Sanatana" is a Sanskrit word which denotes “the eternal or universal laws, and duties we need follow in our life to attain union with absolute or Divine Consciousness. Literally Sanatana means that which is Anadi (beginning less), Ananta (endless) and does not cease to be, that which is eternal and everlasting. Yoga comes from Sanatana Dharma which in modern times known as Hinduism.