This is an optical illusion caused by atmospheric conditions, especially 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. The word comes to English via the French mirage, from the Latin mirari, meaning “to look at, to wonder at”.
I’m definitely in need of a mirage at the moment. The weather has been very gloomy and it would be beautiful to see this.
Have you seen a mirage before?