Reiki (Pronounced ray-key) is a 'laying on hands' healing technique for enhancing the quality of life in all levels - physical, mental, emotional and spiritual.
The word 'Rei' means universal meaning that it is present everywhere.
The word 'ki' means the same as Chi in Chinese. Ki is life energy also known as the vital life force or the universal life force.
Reiki is a spiritually guided energy which allows one to manifest their desires and needs for the highest good of themselves and all connected to them.
While Reiki is spiritual in nature, it is not a religion. It has no dogma, and there is nothing you must believe in order to receive Reiki other than wanting to be healed.