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.

Mitre \Mi"tre\, n. & v.
   See {Miter}.

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®

mitre
     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}, {miter}]
     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: {miter}]
     3: a liturgical headdress worn by bishops on formal occasions
        [syn: {miter}]