The word Reiki actually comes from two Japanese words: Rei and Ki.
The most accepted definition for the word Rei is universal. This, however, is a very general meaning. Without getting too much into the details of the Japanese language, research into the kanji character for Rei reveals a more abundant understanding. In terms of Reiki, the word Rei is interpreted as spiritual consciousness or higher knowledge.
Ki is life energy. The word Ki is synonymous with the Chinese word Chi, the Sanskrit word Prana and Ki or Ti in Hawaiian. This is the non-physical energy that flows through all living things. If there is a restriction in the flow of this energy or this energy within you is low, you are more susceptible to injury or ailment. When this energy flows through you fully and freely you are more capable of living healthy.
Rei (spiritual consciousness) guides Ki (life energy). For this reason, Reiki can be explained as spiritually guided life energy.
Reiki is a very powerful, yet simple Japanese technique founded in the early 1900's by Dr. Mikao Usui for relaxation and reducing stress as well as promoting healing within the body. There are similar Japanese techniques also carried out by "laying on hands" that have been used for thousands of years. Practitioners use Reiki by placing their hands on or above the client with the intention of healing. The energy automatically begins to flow. Reiki does not need to be directed. Reiki instinctively knows where to go and what to do. Connecting with the higher knowledge or higher self that is within the client (as it is in each one of us), this is a very intuitive method for the practitioner. Clients are fully clothed on the table during Reiki Treatment Sessions.