The Collaborative International Dictionary of English v.0.48:

Sawdust \Saw"dust`\, n.
   Dust or small fragments of wood (or of stone, etc.) made by
   the cutting of a saw.
   [1913 Webster]

WordNet (r) 3.0 (2006):

sawdust
    n 1: fine particles of wood made by sawing wood

Moby Thesaurus II by Grady Ward, 1.0:

68 Moby Thesaurus words for "sawdust":
   afterglow, afterimage, air pollution, attritus, balance, bran,
   butt, butt end, candle ends, chaff, cosmic dust, crumb, crumble,
   debris, detritus, dust, dust ball, efflorescence, end, fag end,
   fallout, farina, filings, flour, fossil, grits, groats, holdover,
   husks, kittens, leavings, leftovers, lint, meal, odds and ends,
   offscourings, orts, parings, powder, pussies, rags, raspings,
   refuse, relics, remainder, remains, remnant, residue, residuum,
   rest, roach, rubbish, ruins, rump, scourings, scraps, shadow,
   shavings, smut, soot, straw, stubble, stump, survival, sweepings,
   trace, vestige, waste