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Dictionary.com:
mir·ror /ˈmɪrər/ Pronunciation Key - Show Spelled Pronunciation[mir-er] Pronunciation Key - Show IPA Pronunciation
–noun
1. a reflecting surface, originally of polished metal but now usually of glass with a silvery, metallic, or amalgam backing.
2. such a surface set into a frame, attached to a handle, etc., for use in viewing oneself or as an ornament.
3. any reflecting surface, as the surface of calm water under certain lighting conditions.
4. Optics. a surface that is either plane, concave, or convex and that reflects rays of light.
5. something that gives a minutely faithful representation, image, or idea of something else: Gershwin's music was a mirror of its time.
6. a pattern for imitation; exemplar: a man who was the mirror of fashion.
7. a glass, crystal, or the like, used by magicians, diviners, etc.
–verb (used with object)
8. to reflect in or as if in a mirror.
9. to reflect as a mirror does.
10. to mimic or imitate (something) accurately.
11. to be or give a faithful representation, image, or idea of: Her views on politics mirror mine completely.
–adjective
12. 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.
—Idiom
13. with mirrors, by or as if by magic.
Nope no different universe in the definition.