mirage /miräzh″/ [L, mirari, to look at] , an optical illusion caused by the refraction of light through air layers of different temperatures, such as the illusionary sheets of water that appear to shimmer over stretches of hot sand and pavement. This phenomenon is caused by bending of horizontal light waves upward from the layer of heated air directly over the hot surface. Wind rippling the air layers may produce surprising changes in the shapes and sizes of such mirages. Individuals under severe stress are especially susceptible to interpreting these optic phenomena in bizarre, unrealistic ways.
