The Collaborative International Dictionary of English v.0.48:

Canter \Can"ter\ (k[a^]n"t[~e]r), n. [An abbreviation of
   Canterbury. See Canterbury gallop, under Canterbury.]
   1. A moderate and easy gallop adapted to pleasure riding.
      [1913 Webster]

   Note: The canter is a thoroughly artificial pace, at first
         extremely tiring to the horse, and generally only to be
         produced in him by the restraint of a powerful bit,
         which compels him to throw a great part of his weight
         on his haunches . . . There is so great a variety in
         the mode adopted by different horses for performing the
         canter, that no single description will suffice, nor
         indeed is it easy . . . to define any one of them. --J.
         H. Walsh.
         [1913 Webster]

   2. A rapid or easy passing over.
      [1913 Webster]

            A rapid canter in the Times over all the topics.
                                                  --Sir J.
                                                  Stephen.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Canter \Can"ter\ (k[a^]n"t[~e]r), v. i. [imp. & p. p. Cantered
   (k[a^]n"t[~e]rd); p. pr. & vb. n. Cantering.]
   To move in a canter.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Canter \Can"ter\, v. t.
   To cause, as a horse, to go at a canter; to ride (a horse) at
   a canter.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Canter \Cant"er\, n.
   1. One who cants or whines; a beggar.
      [1913 Webster]

   2. One who makes hypocritical pretensions to goodness; one
      who uses canting language.
      [1913 Webster]

            The day when he was a canter and a rebel.
                                                  --Macaulay.
      [1913 Webster]

WordNet (r) 3.0 (2006):

canter
    n 1: a smooth three-beat gait; between a trot and a gallop [syn:
         canter, lope]
    v 1: ride at a canter; "The men cantered away"
    2: go at a canter, of horses
    3: ride at a cantering pace; "He cantered the horse across the
       meadow"