mirror
n. countablen. a smooth surface, usually made of glass, that shows you an image of yourself or whatever is in front of it. You use it to check your hair or see behind you while driving.
n. a reflective surface, typically of glass with a metal backing, that forms an image by reflection. In computing contexts, it refers to a site or server that contains a duplicate set of data from another to reduce traffic or provide a backup.
I looked in the mirror to fix my tie.
The bathroom mirror was so foggy after the shower that I couldn't see my face.
The architect used a large wall mirror to create the illusion of a much larger living space in the small apartment.
From Middle English mirour, from Old French mireor (“mirror”, literally “looker, watcher”), from mirer (“look at”), from Latin mīror (“wonder at”), from mīrus (“wonderful”), from Proto-Indo-European *smey- (“to laugh, to be glad”). Displaced native Middle English schewere, schawere, from Old English sċēawere (“mirror”, literally “watcher”), which was also the word for "spy".
Commonly used with the preposition 'in' when referring to the image seen ('look in the mirror').