'Fata Morgana' definitions:

Definition of 'fata morgana'

noun

A mirage in the Strait of Messina (attributed to the Arthurian sorcerer Morgan le Fay)

From: GCIDE

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]

From: GCIDE

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]