The Collaborative International Dictionary of English v.0.48:

Shard \Shard\ (sh[aum]rd), n.
   A plant; chard. [Obs.] --Dryden.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Shard \Shard\ (sh[aum]rd), n. [AS. sceard, properly a p. p. from
   the root of scearn to shear, to cut; akin to D. schaard a
   fragment, G. scharte a notch, Icel. skar[eth]. See Shear,
   and cf. Sherd.] [Written also sheard, and sherd.]
   1. A piece or fragment of an earthen vessel, or a like
      brittle substance, as the shell of an egg or snail.
      --Shak.
      [1913 Webster]

            The precious dish
            Broke into shards of beauty on the board. --E.
                                                  Arnold.
      [1913 Webster]

   2. (Zool.) The hard wing case of a beetle.
      [1913 Webster]

            They are his shards, and he their beetle. --Shak.
      [1913 Webster]

   3. A gap in a fence. [Obs.] --Stanyhurst.
      [1913 Webster]

   4. A boundary; a division. [Obs. & R.] --Spenser.
      [1913 Webster]

WordNet (r) 3.0 (2006):

shard
    n 1: a broken piece of a brittle artifact [syn: shard,
         sherd, fragment]

Moby Thesaurus II by Grady Ward, 1.0:

114 Moby Thesaurus words for "shard":
   abrade, atomize, beat, bit, bones, bray, break, brecciate, butt,
   chaff, chip, chunk, clip, clipping, collop, comminute,
   contriturate, crumb, crumble, crush, culm, cut, cutting, deadwood,
   dishwater, disintegrate, dollop, draff, dregs, dust, end,
   fall to pieces, filings, flour, fragment, garbage, gash, gob,
   gobbet, grain, granulate, granulize, grate, grind, grind to powder,
   hogwash, hunk, husks, leavings, lees, levigate, lump, mash, mill,
   modicum, moiety, morsel, offal, offscourings, orts, paring,
   parings, particle, pestle, piece, potsherds, pound, powder,
   pulverize, rags, rasher, raspings, reduce to powder, refuse, scoop,
   scourings, scrap, scrap iron, scraps, scrunch, scum, shards,
   shatter, shaving, shavings, shiver, shred, slack, slag, slice,
   sliver, slop, slops, smash, smithereen, snack, snatch, snip,
   snippet, splinter, squash, stitch, stubble, stump, sweepings,
   swill, tares, tatter, triturate, wastage, waste, waste matter,
   wastepaper, weeds