mi·rage / məˈräzh/ • n. an optical illusion caused by atmospheric conditions, esp. the appearance of a sheet of water in a desert or on a hot road caused by the refraction of light from the sky by heated air. ∎  something that appears real or possible but is not in fact so: the notion that the public is pro-business is a mirage.

mirage Type of optical illusion sometimes seen near the Earth's surface when light is refracted (bent) as it passes between cool dense air to warmer, less dense air. Mirages are most commonly seen shimmering on hot, dry roads; the shimmer is a refracted image of the sky.

mirage XIX. — F. mirage, f. mirer refl. look at oneself in a mirror — L. mīrāre; see prec., -AGE.

mirage An optical effect in which major vertical variation in temperature of the lower atmosphere produces differential refraction of light, resulting, for example, in raised images and in gaps, which may give the appearance of a water surface.

mirage Optical effect in which major vertical variation in temperature of the lower atmosphere produces differential refraction of light, resulting for example in raised images and in gaps, which may give the appearance of a water surface.