Yoga

What it isn't?
A lot of people misinterpret Yogic Science as a bunch of people bending themselves into weird positions which is only one aspect of it. When westerners think if Yoga they it is a dicipline of yoga named: Hatha_Yoga.

No reason to 're-invent the wheel' here, Wikipedia has already done an extensive job explaining what Yoga is, check it out

Related:
 * Hatha Yoga
 * Meditation
 * Breath
 * Nadis