The meaning of 'Trompe l'oeil' in art

The term trompe l'oeil when applied to art refers to the artistic technique whereby the artist uses highly realistic imagery to create an optical illusion. In order to convey objects that are depicted within a painting, or drawing, as three-dimensional. This helps the overall drama and movement of the composition.

An example of the use of the artistic technique of trompe l'oeil.
By the artist Andrea Mantegna, this image is of the oculus on the
ceiling of the central chamber, at the castle San Giorgio in Mantua.