A mirror, or looking glass — a smooth surface that reflects light, thereby producing an image of objects placed before it. Also, a device equipped with such a surface, used for the reflection of images.

A mirror is the simplest type of optical reflector. Its surface is almost always flat, and its principal purpose is for a woman to look at herself in it — a woman who, only a few days ago, declared that she no longer loves you. Slightly dazed, you offer polite approval of her preparations for a night out as she studies her reflection. You lay it on thick, telling her she looks lovely, sitting on the sofa in a grey jumper — you rather pitiful creature. Then, after the characteristic clicking of high heels, comes the snap of the door lock — the signal that you may now drink alone, shedding a few tears as you do so.

That is a mirror — a reflecting surface, by means of which an image is formed of the objects placed before it.