The Collaborative International Dictionary of English v.0.48:

Gallop \Gal"lop\, v. i. [imp. & p. p. Galloped; p. pr. & vb.
   n. Galloping.] [OE. galopen, F. galoper, of German origin;
   cf. assumed Goth. ga-hlaupan to run, OHG. giloufen, AS.
   gehle['a]pan to leap, dance, fr. root of E. leap, and a
   prefix; or cf. OFlem. walop a gallop. See Leap, and cf. 1st
   Wallop.]
   1. To move or run in the mode called a gallop; as a horse; to
      go at a gallop; to run or move with speed.
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            But gallop lively down the western hill. --Donne.
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   2. To ride a horse at a gallop.
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   3. Fig.: To go rapidly or carelessly, as in making a hasty
      examination.
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            Such superficial ideas he may collect in galloping
            over it.                              --Locke.
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The Collaborative International Dictionary of English v.0.48:

Gallop \Gal"lop\, v. t.
   To cause to gallop.
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The Collaborative International Dictionary of English v.0.48:

Gallop \Gal"lop\, n. [Cf. F. galop. See Gallop, v. i., and cf.
   Galop.]
   A mode of running by a quadruped, particularly by a horse, by
   lifting alternately the fore feet and the hind feet, in
   successive leaps or bounds.
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   Hand gallop, a slow or gentle gallop.
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WordNet (r) 3.0 (2006):

gallop
    n 1: a fast gait of a horse; a two-beat stride during which all
         four legs are off the ground simultaneously
    v 1: ride at a galloping pace; "He was galloping down the road"
    2: go at galloping speed; "The horse was galloping along"
    3: cause to move at full gallop; "Did you gallop the horse just
       now?" [syn: gallop, extend]