Virtual image

In optics, a virtual image is an image formed when the outgoing rays from an object always diverge (move apart). A plane mirror forms a virtual image positioned behind the mirror. Light from the source only exists in front of the mirror. The image in a plane mirror appears to be as far behind the mirror as the object is in front of the mirror.
In contrast, a real image is one that is formed when the outgoing rays form a point converge at a real location. Real images can be projected onto a diffuse reflecting screen, but a screen is not necessary for the image to form.