Reiki comes from two Japanese words which translate to "universal life force." This universal life force is an energy found within all things -- people, animals, plants, rocks, trees… even the earth itself. Someone trained in the use of Reiki channels that life force, allowing the recipient to receive the healing energy.
REI as it is used in Reiki is interpreted to mean spiritual consciousness. This is the knowledge that comes from God, The Universe, The Higher Self, The Holy Ghost, and That which is All-Knowing
KIis life force, the nonphysical energy that animates all livings, the primary energy. It is the energy used by all healers and surrounds us.