The Collaborative International Dictionary of English v.0.48:

Ashes \Ash"es\, n. pl. [OE. asche, aske, AS. asce, [ae]sce, axe;
   akin to OHG. asca, G. asche, D. asch, Icel. & Sw. aska, Dan.
   aske, Goth. azgo.]
   1. The earthy or mineral particles of combustible substances
      remaining after combustion, as of wood or coal.
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   2. Specifically: The remains of the human body when burnt, or
      when "returned to dust" by natural decay.
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            Their martyred blood and ashes sow.   --Milton.
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            The coffins were broken open. The ashes were
            scattered to the winds.               --Macaulay.
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   3. The color of ashes; deathlike paleness.
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            The lip of ashes, and the cheek of flame. --Byron.
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   In dust and ashes, In sackcloth and ashes, with humble
      expression of grief or repentance; -- from the method of
      mourning in Eastern lands.

   Volcanic ashes, or Volcanic ash, the loose, earthy
      matter, or small fragments of stone or lava, ejected by
      volcanoes.
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Moby Thesaurus II by Grady Ward, 1.0:

57 Moby Thesaurus words for "ashes":
   ash, body, bones, brand, cadaver, calx, carbon, carcass, carrion,
   charcoal, cinder, cinders, clay, clinker, clinkers, coal, coke,
   coom, corpse, corpus delicti, crowbait, dead body, dead man,
   dead person, decedent, dross, dry bones, dust, earth,
   embalmed corpse, food for worms, fume, late lamented, lava,
   mortal remains, mummification, mummy, organic remains, reek,
   relics, reliquiae, remains, scoria, skeleton, slag, smoke, smudge,
   smut, soot, stiff, sullage, tenement of clay, the dead,
   the deceased, the defunct, the departed, the loved one



Easton's 1897 Bible Dictionary:

Ashes
   The ashes of a red heifer burned entire (Num. 19:5) when
   sprinkled on the unclean made them ceremonially clean (Heb.
   9:13).

     To cover the head with ashes was a token of self-abhorrence
   and humiliation (2 Sam. 13:19; Esther 4:3; Jer. 6:26, etc.).

     To feed on ashes (Isa. 44:20), means to seek that which will
   prove to be vain and unsatisfactory, and hence it denotes the
   unsatisfactory nature of idol-worship. (Comp. Hos. 12:1).