What is a mirage?
A mirage is a naturally occurring optical phenomenon in which light rays are bent to produce a displaced image of distant objects or the sky.
It is a real optical phenomenon which can be captured on camera, since light rays actually are refracted to form the false image at the observer's location.
What the image appears to represent is determined by the interpretive faculties of the human mind.
A common example of a mirage is the appearance of water some distance down the highway on a hot summer day.