Source : Webster's Revised Unabridged Dictionary (1913)

Miter \Mi"ter\, Mitre \Mi"tre\, v. t. [imp. & p. p. {Mitered}or
   {Mitred}; p. pr. & vb. n. {Mitering}or {Mitring}.]
   1. To place a miter upon; to adorn with a miter. ``Mitered
      locks.'' --Milton.

   2. To match together, as two pieces of molding or brass rule
      on a line bisecting the angle of junction; to bevel the
      ends or edges of, for the purpose of matching together at
      an angle.

Miter \Mi"ter\, Mitre \Mi"tre\, n. [F. mitre, fr. L. mitra
   headband, turban, Gr. ?.]
   1. A covering for the head, worn on solemn occasions by
      church dignitaries. It has been made in many forms, the
      present form being a lofty cap with two points or peaks.
      --Fairholt.

   2. The surface forming the beveled end or edge of a piece
      where a miter joint is made; also, a joint formed or a
      junction effected by two beveled ends or edges; a miter
      joint.

   3. (Numis.) A sort of base money or coin.

   {Miter box} (Carp. & Print.), an apparatus for guiding a
      handsaw at the proper angle in making a miter joint; esp.,
      a wooden or metal trough with vertical kerfs in its
      upright sides, for guides.

   {Miter dovetail} (Carp.), a kind of dovetail for a miter
      joint in which there is only one joint line visible, and
      that at the angle.

   {Miter gauge} (Carp.), a gauge for determining the angle of a
      miter.

   {Miter joint}, a joint formed by pieces matched and united
      upon a line bisecting the angle of junction, as by the
      beveled ends of two pieces of molding or brass rule, etc.
      The term is used especially when the pieces form a right
      angle. See {Miter}, 2.

   {Miter shell} (Zo["o]l.), any one of numerous species of
      marine univalve shells of the genus {Mitra}.

   {Miter square} (Carp.), a bevel with an immovable arm at an
      angle of 45[deg], for striking lines on stuff to be
      mitered; also, a square with an arm adjustable to any
      angle.

   {Miter wheels}, a pair of bevel gears, of equal diameter,
      adapted for working together, usually with their axes at
      right angles.

Miter \Mi"ter\, Mitre \Mi"tre\, v. i.
   To meet and match together, as two pieces of molding, on a
   line bisecting the angle of junction.

Source : WordNet®

miter
     n 1: joint that forms a corner; usually both sides are bevelled
          at a 45-degree angle to form a 90-degree corner [syn: {miter
          joint}, {mitre joint}, {mitre}]
     2: the surface of a beveled end of a piece where a miter joint
        is made; "he covered the miter with glue before making the
        joint" [syn: {mitre}]
     3: a liturgical headdress worn by bishops on formal occasions
        [syn: {mitre}]
     v 1: bevel the edges of, to make a miter joint
     2: confer a miter on (a bishop)
     3: fit together in a miter joint