Patanjali describes yoga
  अथ योगानुशासनम् ॥१॥  atha yogānuśāsanam ||1||   “Here is the instruction in Yoga.”   योगश्चित्तवृत्तिनिरोधः ॥२॥  yogaś cittavṛtti nirodhaḥ ||2||   “Yoga is the control of the activity of the mind.”   तदा द्रष्टुः स्वरूपेऽवस्थानम् ॥३॥  tadā draṣṭuḥ svarūpe’vasthānam ||3||   “Then seer abides in itself.”    (Yoga Sutras 1-3)