आसन Āsana means sitting.

 आसन Āsana means sitting. 

"Eh what?" I hear you say, "I thought āsana meant a yoga posture!" (ha ha) 

Please allow me to explain. Contrary to popular misconception, what mostly everyone calls 'yoga' i.e. Haṭha-yoga, is actually just one small part of Aṣṭanga-yoga, which is in turn part of Jñana-yoga, a part of the larger picture of the three main yogas:-

1. Bhakti-yoga 

2. Jñana-yoga 

3. Karma-yoga

The practice of sitting to meditate is one of the Eight Limbs of Patanjali's Aṣṭanga-yoga. Separately, Haṭha-yoga is one such limb, a subset consisting of the discipline of regulated breath control achieved though various postures. Āsana actually means sitting - it wasn't until modern times (19th century) that it was used to mean the various yoga postures i.e. standing, lying, bending, etc of Haṭha-yoga. 

To Patanjali, āsana meant holding a positition in order to meditate. The best posture to maintain prolonged trance is sitting. If you lie down, chances are you'll fall asleep. If you stand, you'll fall over. To the modern yoga practitioner in the West it means anything but sitting! This is because the first Indian yogis who introduced it to America and Europe did not emphasise meditation - they were stuck on that level, that yoga rung, and could not rise higher on the yoga ladder due to bodily identification - possibly from doing too much Haṭha-yoga and not enough meditation haha! (or japa, or kirtan, or bhajans etcetera) 

To this day, mention the word 'yoga' and the first thing that enters people's minds is 'exercise positions'. It is a sad state of affairs because that posturing only makes up about 1-5% of the complete Yoga Ladder with all its various rungs. You can blame that on Vivekanda. 

The idea is to start at the bottom and work one's way up once each level of perfection is attained on subsequent rungs. It begins with Karma-yoga, charitable work. Practically every thing we do in life is aimed at reaping the fruits of our labour - and the first principle in yoking with the Divine (the etymological root of yoke is 'yog' Sanskrit for to 'join up') is letting go of selfish gains. 

Karma-yoga is a 'physical' yoga (if you like), and Haṭha-yoga is the next logical extension, using the body and controlling the breath in order to balance the airs, the vital life-forces that move between the chakras.

The purpose of all this is to be able to meditate undisturbed as in Jñana-yoga. By practicing breath control and postures (Haṭha-yoga) one is able to quieten the body so as to be able to sit (āsana) for long periods in order to go deeper and deeper into meditation.

The focus, the object of meditation (Jñana-yoga) is the Supersoul, the part of God that resides in the heart of every living being. The Yogi meditates on the Supersoul to seek union with the Divine. That is the true meaning of yoga - not a paid-for workout on foam mats in a class, or a trendy display of gymnastic ability. That is not Yoga, real in its true essence! 

#Note: I heard from one source that in 1811 or 1834 possibly the Sritattvanidi of the then Maharaj of Mysore, Krishnaraj Wodeyar III (1794 to 1868) wanting to compile a manuscript/treatise of South India of that time, funded the effort to put everything together including instructions and illustrations of 122 postures. 

Some of the first Haṭha-yogis who became famous in the West after introducing 'yoga' were Swami Vivekanda in the late 1800s and his disciple Pramahamsa Yogananda in the 1920s. They did not teach much (withheld?) if anything of the rest of the limbs of Patanjali's Eightfold Yoga System and virtually nothing on the other two main paths. Although karma was discussed there was little mention of Karma-yoga eg the kind of community service performed by Christians and other charitable institutions and philanthropists. There was no emphasis on Bhakti-yoga as introduced by Śrīla Prabhupāda in the 60s, and only a little of the Jñana-yoga of meditation popularised from the Hippie era and onwards by 'hip gurus' such as Gurdjieff, Rajneesh (the Orange People), Muktananda, Chinmoy, Maharishi Mahesh Yogi of TM (Transcendental Meditation) and Maharaj Ji (Prem Rawat) of the Divine Light Mission etcetera. That is why everyone thinks of āsanas when you say the word 'Yoga'. 

Very sad indeed. Only 1-5% of the real meaning of yoga.