A perspective (perspective, n. 2a). Also: a scrying glass, a magic mirror. Also figurative.

(a) a mirror fixed or positioned to the side of something, esp. a window or larger mirror; (b) spec. (chiefly North American) a mirror projecting…

a mirror at the fixed point of the index-arm in an astronomical or surveying instrument, from which the light is reflected to the horizon-glass.

A somewhat convex dark or coloured hand-mirror, used to concentrate the features of a landscape in subdued tones. Sometimes applied to coloured…

A device, usually in the form of a vertical cylindrical mirror, made so as to give a correct image of an anamorphosis (see anamorphosis, n. 1).

(a) a magnetized surface that reflects light; (b) a magnetic field that reflects charged particles.

A small concave mirror (see quot. 1890). Obsolete. rare.

U.S. A mirror or mirrors set at the side of a building and so angled as to reflect a view of the street to people inside. Now chiefly historical.

The hindmost mirror or reflective surface in a spectroscope or other instrument. Also: a reflecting mirror behind a lamp or light source.

= three-way mirror at three-way, adj. a.

Having, or connected with, three ways, roads, or channels; situated where three ways meet. Also, involving three participants. three-way cock, three…

two-way mirror, a mirror which lets through enough light for an observer at the back to see through it, without being seen from the front.