Miter

n. [Fr. mitre, It. & Sp. mitra, from Lat. mitra, Gr. μίτρα, head-band, turban.]

1. A covering for the head, worn on solemn occasions by bishops, cardinals, and the abbots of certain monasteries, and, from special privilege, by the canons of certain churches. Its form was originally low, with the sides straight. Its height was afterward increased, till it took the present form of a lofty cap with two peaks.
2. (Arch.) An angle of 45°, or, more properly, the joint formed by the ends of two pieces, as of molding, each cut off at an angle of 45°, and matching together so as to form a right angle. The term is also applied to pieces meeting at any other angle, and matching together on a line bisecting the angle.
3. (Irish Hist.) A sort of base money or coin.

Miter-joint, a joint formed by pieces matched and united upon a line bisecting the angle of junction. — Miter-square (Carp.), a bevel with an arm immovable at an angle of 45°, for striking lines on stuff to be mitered. — Miter-wheels, a pair of bevel wheels, of equal diameter, working together, usually with their axes at right angles.