What is "pratyahara"

n. (context yoga English) The withdrawal of one's senses; focus on oneself as opposed to external stimuli. (from 19th c.)

Pratyahara ( Devanāgarī प्रत्याहार, Tibetan སོ་སོར་སྡུད་པ་, Wylie so sor sdud pa) or the 'withdrawal of the senses' is the fifth element among the Eight stages of Patanjali's Ashtanga Yoga, as mentioned in his classical work, Yoga Sutras of Patanjali composed in the 2nd century BCE. It is also the first stage of the six-branch yoga (ṣaḍaṅgayoga) of the Buddhist Kālacakra tantra, where it refers to the withdrawal of the five senses from external objects to be replaced by the mentally created senses of an enlightened deity. This phase is roughly analogous to the physical isolation (kāyaviveka, Tib. lus bden) phase of Guhyasamāja tantra.

For Patanjali, it is a bridge between the bahiranga (external) aspects of yoga namely, yama, niyama, asana, pranayama, and the antaranga (internal) yoga. Having actualized the pratyahara stage, a practitioner is able to effectively engage into the practice of Samyama. At the stage of pratyahara, the consciousness of the individual is internalized in order that the sensations from the senses of taste, touch, sight, hearing and smell don't reach their respective centers in the brain and takes the sadhaka (practitioner) to next stages of Yoga, namely Dharana (concentration) and Dhyana (meditation), and Samadhi (mystical absorption), being the aim of all Yogic practices.