The Sanskrit word yoga has many meanings, and is derived from the Sanskrit root "yuj", meaning "to control", "to yoke" or "to unite". Translations include "joining", "uniting", "union", "conjunction", and "means". It is also possible that the word yoga derives from "yujir samadhau," which means "contemplation" or "absorption." This translation fits better with the dualist Raja Yoga because it is through contemplation that discrimination between prakrti (nature) and purusha (pure consciousness) occurs. (Wikipedia)
Kundalini Yoga
Raja Yoga
Many people have a limited understanding of yoga, thinking that it is restricted to the asana practice of increasing flexibility, toning up muscles, relaxing the body, increasing strength, improving balance and finding stress relief. While yoga does all of the above that is a limited view of what yoga really has to offer us. The true purpose of yoga is to develop a relationship with the self that exists deep within our core, which is called Jivatman (individual soul). Jivatman is a unity of Atman, the supreme soul, or Brahman, that is always there, unchanging and endlessly radiating the energy of peace, love and compassion.
According to the Upanishads, our human nature, or prakriti, is comprised of five different dimensions. Our mortal body, (the temple of our individualized atman) expands into more subtle layers of energy around our spiritual center. Human beings consist of five distinct energy sheaths called “koshas” that surround our jivatman. Each kosha vibrates at different speeds, and they interact and overlap with each other, ranging from gross to transcendental dimensions.
The pancha koshas (five sheaths) provide us with a road map for better understanding of our psychological and spiritual development. There are namely:
Physical – Annamaya kosha
Energy – Pranamaya kosha
Mental – Manamaya kosha
Wisdom – Vijnanamaya kosha
Bliss – Anandamaya kosha
Self – Atman
http://www.intuitiveflow.com/the-five-koshas-pancha-kosha/
The reason why certain religions teach that yoga & meditation are 'demonic' & satanic' is because of what happened hundreds of years ago. When Britain invaded India, they had trouble controlling the population, whom were very in tune with their bodies. Due to dedicated ancient Yoga and Meditation practices, many Indians had developed 'Siddhis' (special abilities unexplained by modern science like levitation, telekinesis, psychic and shamanic powers etc). This is why the control system had the church teach that yoga and meditation were evil, to try and stop others from developing these innate human abilities, which threaten their control. [anon]
See Also
Atonement
Awakening
Buddhism
Consciousness
Christ Consciousness
Figure 1.6 - From One Mind comes all. All goes back to One Mind
Hinduism
Kaibalyam
Kriya Sutras
Meditation
Thought
Volition
Will
2.24 - The Duality of One