The Collaborative International Dictionary of English v.0.48:

Dapple \Dap"ple\, n. [Cf. Icel. depill a spot, a dot, a dog with
   spots over the eyes, dapi a pool, and E. dimple.]
   One of the spots on a dappled animal.
   [1913 Webster]

         He has . . . as many eyes on his body as my gray mare
         hath dapples.                            --Sir P.
                                                  Sidney.
   Dapple

The Collaborative International Dictionary of English v.0.48:

Dapple \Dap"ple\, Dappled \Dap"pled\, a.
   Marked with spots of different shades of color; spotted;
   variegated; as, a dapple horse.
   [1913 Webster]

         Some dapple mists still floated along the peaks. --Sir
                                                  W. Scott.
   [1913 Webster]

   Note: The word is used in composition to denote that some
         color is variegated or marked with spots; as,
         dapple-bay; dapple-gray.
         [1913 Webster]

               His steed was all dapple-gray.     --Chaucer.
         [1913 Webster]

               O, swiftly can speed my dapple-gray steed. --Sir
                                                  W. Scott.
         [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Dapple \Dap"ple\, v. t. [imp. & p. p. Dappled; p. pr. & vb. n.
   Dappling.]
   To variegate with spots; to spot.
   [1913 Webster]

         The gentle day, . . .
         Dapples the drowsy east with spots of gray. --Shak.
   [1913 Webster]

         The dappled pink and blushing rose.      --Prior.
   [1913 Webster]

WordNet (r) 3.0 (2006):

dapple
    n 1: a small contrasting part of something; "a bald spot"; "a
         leopard's spots"; "a patch of clouds"; "patches of thin
         ice"; "a fleck of red" [syn: spot, speckle, dapple,
         patch, fleck, maculation]
    v 1: colour with streaks or blotches of different shades [syn:
         mottle, dapple, cloud]

Moby Thesaurus II by Grady Ward, 1.0:

202 Moby Thesaurus words for "dapple":
   Quaker-colored, acier, ashen, ashy, band, bar, bespangle,
   bespeckle, bespot, birthmark, blaze, blaze a trail, blemish,
   blotch, brand, brindled, calico, canescent, caste mark, chalk,
   chalk up, check, check off, checker, checkmark, cicatrix,
   cicatrize, cinereous, cinerous, clouded, cut, dapple-gray, dappled,
   dappled-gray, dappledness, dappleness, dash, define, delimit,
   demarcate, dingy, discolor, discoloration, dismal, dot, dotted,
   dottedness, dove-colored, dove-gray, dreary, dull, dusty, earmark,
   engrave, engraving, flake, flea-bitten, fleck, flecked, flick,
   freckle, freckliness, gash, glaucescent, glaucous, graving, gray,
   gray-black, gray-brown, gray-colored, gray-drab, gray-green,
   gray-spotted, gray-toned, gray-white, grayed, grayish, griseous,
   grizzle, grizzled, grizzly, hack, harlequin, hatch, impress,
   imprint, iris, iron-gray, jot, lead-gray, leaden, lentigo, line,
   livid, macula, maculate, maculation, macule, make a mark, marble,
   marbled, marbleize, mark, mark off, mark out, marking, mole,
   motley, mottle, mottled, mottledness, mouse-colored, mouse-gray,
   mousy, nevus, nick, notch, paint, patch, pearl, pearl-gray, pearly,
   pencil, pepper, pepper-and-salt, piebald, pied, pinto, point,
   pointillage, pointillism, polka dot, polychrome, polychromize,
   prick, print, punch, punctuate, puncture, rainbow, riddle, sad,
   scar, scarification, scarify, score, scotch, scratch, scratching,
   seal, seam, silver, silver-gray, silvered, silvery, skewbald,
   slate-colored, slaty, smoke-gray, smoky, sober, somber, spangle,
   speck, speckle, speckled, speckliness, splash, splotch, spot,
   spotted, spottedness, spottiness, sprinkle, stain, stamp,
   steel-gray, steely, stigma, stigmatize, stipple, stippledness,
   stippling, stone-colored, strawberry mark, streak, striate, stripe,
   stud, tattoo, tattoo mark, taupe, tessellate, tick, tick off,
   tittle, trace, underline, underscore, variegate, vein, watermark