Yoga means Union, the union of our spiritual, mental and physical being, it provides us with a way to reach this union or Enlightenment.
The antiquity, accuracy and extraordinary vitality of the "sacred science" from the sages of ancient Indian civilization is what is known as YOGA.
The word Yoga has two main meanings:
1) Union.
2) The means or techniques for reaching that union.
In the first sense, Yoga means all kinds of unions. In India’s philosophical and religious systems it is used in the sense of making the union of the spiritual principle of man (Atma) with divinity (Brahma), but it also means the conscious union of the material aspect of man with his spiritual aspect, and of the superficial personality with the deep personality. In other words it is the state of integration, of conscious unification of the superficial, deep and higher aspects of man.
In the second sense, Yoga is the set of precise and systematic techniques that lead to the development of certain levels of consciousness, not updated in most men, and the integration of such levels into a single unit of total and permanent consciousness.
You will find much more about “yoga” in the Knowledge section.