Reiki, is "Universal Life Force" or "Universal Energy". The Ki in Reiki refers to the energy component. Different cultures recognize life energy and call it by different names. Ki is used in Japan. Chi is another name for basic life energy, also used in the East. The discipline of Tai Chi is learning how to work with this force. Hindu traditions call it Prana. Hawaiian shamans call it Manna. Rauch is the Hebrew term for this force. Numen, Odic force and Orgone are all variant names. Various cultures have various definitions, interpretations, and associations for it, but basically they are all talking about the same life energy.
This life force is found everywhere and in all things, including people, animals, and plants. The energy is universal, denoted by the Rei in Reiki, not personal. The universal part of the Reiki definition signifies not only that this basic energy is found in everything, universally, but also that as a system of healing, we are drawing upon this energy from the universe, which is limitless and ever abundant, rather than drawing upon our own personal "Ki" or that of another person, animal, plant or object