The Collaborative International Dictionary of English v.0.48:

Stipple \Stip"ple\, v. t. [imp. & p. p. Stippled; p. pr. & vb.
   n. Stippling.] [D. stippelen to make points, to spot, dot,
   from stippel, dim. of stip a dot, spot.]
   1. To engrave by means of dots, in distinction from engraving
      in lines.
      [1913 Webster]

            The interlaying of small pieces can not altogether
            avoid a broken, stippled, spotty effect. --Milman.
      [1913 Webster]

   2. To paint, as in water colors, by small, short touches
      which together produce an even or softly graded surface.
      [1913 Webster] Stipple

WordNet (r) 3.0 (2006):

stippled
    adj 1: having a pattern of dots [syn: dotted, flecked,
           specked, speckled, stippled]

Moby Thesaurus II by Grady Ward, 1.0:

34 Moby Thesaurus words for "stippled":
   bespangled, blotched, blotchy, dotted, dotty, flea-bitten, flecked,
   fleckered, frecked, freckled, freckly, macular, maculate,
   maculated, patchy, peppered, pocked, pockmarked, pocky, pointille,
   pointillistic, polka-dot, punctated, spangled, specked, speckled,
   speckledy, speckly, splotched, splotchy, spotted, spotty,
   sprinkled, studded