<p><strong>Noun</strong></p><ul><li>A reflecting surface, originally of polished metal but now usually of glass with a silvery, metallic, or amalgam backing.</li><li>Such a surface set into a frame, attached to a handle, etc., for use in viewing oneself or as an ornament.</li><li>Any reflecting surface, as the surface of calm water under certain lighting conditions.</li><li>Optics: a surface that is either plane, concave, or convex and that reflects rays of light.</li><li>Something that gives a minutely faithful representation, image, or idea of something else: Gershwin's music was a mirror of its time.</li><li>A pattern for imitation; exemplar: a man who was the mirror of fashion.</li><li>A glass, crystal, or the like, used by magicians, diviners, etc.</li></ul><p><strong>Verb</strong></p><ul><li>(used with object) To reflect in or as if in a mirror.</li><li>To reflect as a mirror does.</li><li>To mimic or imitate (something) accurately.</li><li>To be or give a faithful representation, image, or idea of: Her views on politics mirror mine completely.</li></ul><p><strong>Adjective</strong></p><ul><li>Music: (of a canon or fugue) capable of being played in retrograde or in inversion, as though read in a mirror placed beside or below the music.</li></ul>