siddhis are integral to the entirety of Hindu beliefs from their earliest Vedic beginnings right up until the ongoing hagiographies of modern Hindu mystics… the most applicable definition of yoga is precisely that of attainment of mystical powers
Bryant, drawing on White, argues that siddhis are not a peripheral curiosity but the historically primary referent of yoga itself, continuous from the Upaniṣads through the Tantras.
, The Yoga Sutras of Patanjali: A New Edition, Translation, and Commentary, 2009thesis