From Wiktionary

Etymology

From Sanskrit आसन (“‘sitting down’”) < आस (“‘to sit down’”)

Noun

asana (plural asanas)

A body position, typically associated with the practice of yoga.

From wordnet.princeton.edu

(n.) (Hinduism) a posture or manner of sitting (as in the practice of yoga)

From Wikipedia

Asana…is a body position, typically associated with the practice of Yoga, intended primarily to restore and maintain a practitioner’s well-being, improve the body’s flexibility and vitality, and promote the ability to remain in seated meditation for extended periods. These are widely known as Yoga postures or Yoga positions, which is currently practiced for exercise and as alternate medicine.

Check out http://en.wikipedia.org/wiki/Asana for detailed information.

From Miss Bite Size

Asana is what people generally mean when they say they practice yoga. I thought yoga IS asana until I read B.K.S. Iyengar’s Light on Yoga and Patanjali’s Yoga Sutras and learned that asana is the third of the eight limbs (ashtanga) of Raja Yoga (one of many schools of yoga, what we know as Yoga), just one aspect of many steps to enlightenment or union with the universe.

So the eight limbs are (in order) yamas (rules on what not to do), niyamas (rules on what to do), asanas, pranayama (breath control), pratyahara (withdrawing of the senses), dhrana (concentration of the mind), dhyana (meditation) and samadhi (heightened state of consciousness) – sweet! We’ll discuss the limbs in upcoming articles, but that is the general idea.