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)