Asana is the term for a stance or posture in HATHA YOGA. It is from the root as (to sit). Some say that there were originally 8,400,000 asanas to rep-resent the 8,400,000 births that each individual must pass through before he or she becomes liberated. There are said to be only a few hundred in practice today; 84 is the number most often presented to students.
An asana is a means to focus the mind so that it becomes steady, calm, and quiet. It is not intended as any sort of physical exercise per se, despite being commonly understood that way in the West. The various asanas are intended to open up different subtle energy channels in the body and the psychic centers (CHAKRAS) that run along the spine. It is understood that the total command of the body at both gross and subtle levels is a path to the total command of the mind. Total command of the mind can lead to the steady, calm, and quiet poise of being, where the highest reality of self and universe can be directly perceived. Breath control, or pranayama, is always a part of asana practice.
Further reading: Nicolai Bachman, The Language of Yoga: Complete A–Y Guide to Asana Names, Sanskrit Terms and Chants (Boulder, Colo.: Sounds True, 2005); B. K. S. Iyengar, Light on Yoga, rev. ed. (New York: Schocken Books, 1979); Ajit Mookerjee, Tantra Asana: A Way to Self-Realization (Basel: Ravi Kumar, 1971); Swami Satyananda Saraswati, Asana Pranayama Mudra Bandha (Bihar: Bihar School of Yoga, 1999); Jayadeva Yogendra, Cyclopedia Yoga with Special Information on Asana (Bombay: Yoga Institute, 1988).
Encyclopedia of Hinduism. A. Jones and James D. Ryan. 2007.