The Collaborative International Dictionary of English v.0.48:

Mirage \Mi`rage"\, n. [F., fr. mirer to look at carefully, to
   aim, se mirer to look at one's self in a glass, to reflect,
   to be reflected, LL. mirare to look at. See Mirror.]
   An optical effect, sometimes seen on the ocean, but more
   frequently in deserts, due to total reflection of light at
   the surface common to two strata of air differently heated.
   The reflected image is seen, commonly in an inverted
   position, while the real object may or may not be in sight.
   When the surface is horizontal, and below the eye, the
   appearance is that of a sheet of water in which the object is
   seen reflected; when the reflecting surface is above the eye,
   the image is seen projected against the sky. The fata
   Morgana and looming are species of mirage.
   [1913 Webster]

         By the mirage uplifted the land floats vague in the
         ether,
         Ships and the shadows of ships hang in the motionless
         air.                                     --Longfellow.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Fata Morgana \Fa"ta Mor*ga"na\ [It.; -- so called because this
   phenomenon was looked upon as the work of a fairy (It. fata)
   of the name of Morg['a]na. See Fairy.]
   A kind of mirage by which distant objects appear inverted,
   distorted, displaced, or multiplied. It is noticed
   particularly at the Straits of Messina, between Calabria and
   Sicily.
   [1913 Webster]

WordNet (r) 3.0 (2006):

fata morgana
    n 1: a mirage in the Strait of Messina (attributed to the
         Arthurian sorcerer Morgan le Fay)

Moby Thesaurus II by Grady Ward, 1.0:

30 Moby Thesaurus words for "fata morgana":
   autoluminescence, bioluminescence, cathode luminescence,
   chemicoluminescence, chemiluminescence, corposant,
   crystalloluminescence, double corposant, electroluminescence,
   fluorescence, fox fire, ignis fatuus, looming, luciferase,
   luciferin, luminescence, luminophor, marshfire, mirage,
   noctiluscence, phosphor, phosphorescence, photoluminescence,
   radioluminescence, thermoluminescence, tribofluorescence,
   triboluminescence, tribophosphorescence, wisp, witch fire