Wheel of Life

Definition of Reiki

REIKI is pronounced "Ray Key."

REI means universal, unlimited or boundless, and refers also to the spiritual
       (cosmic) dimension and the soul.

KI means the vital life force energy which flows through all that is alive
(all kingdoms of form-plant, mineral and animal).

These japanese characters, when combined, present the concept of "
universal life-energy".  REIKI energy is whole, not dual- it is, therefore, neither positive or negative per se but rather is the combination of these qualities.
Not yin or yang but whole or one.

REIKI is universal energy-therefore, it is safely used at anytime or any place.
 It expresses the quality of "unconditional" rather than "conditional"
"Universal" means "applicable or common to all purposes, conditions, or situations," and pertains to that which is cosmic.