[1] : The Collaborative International Dictionary of English v.0.48

ash \ash\, n.,
   sing. of ashes.
   1913 webster

   note: ash is rarely used in the singular except in connection
         with chemical or geological products; as, soda ash,
         coal which yields a red ash, etc., or as a qualifying
         or combining word; as, ash bin, ash heap, ash hole, ash
         pan, ash pit, ash-grey, ash-colored, pearlash, potash.
         1913 webster

   bone ash, burnt powered; bone earth.

   volcanic ash. see under ashes.
      1913 webster
see also:
ashes bone ash volcanic ash 

[2] : The Collaborative International Dictionary of English v.0.48

ashes \ash"es\, n. pl. oe. asche, aske, as. asce, aesce, 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.
      1913 webster

   2. specifically: the remains of the human body when burnt, or
      when "returned to dust" by natural decay.
      1913 webster

            their martyred blood and ashes sow.   --milton.
      1913 webster

            the coffins were broken open. the ashes were
            scattered to the winds.               --macaulay.
      1913 webster

   3. the color of ashes; deathlike paleness.
      1913 webster

            the lip of ashes, and the cheek of flame. --byron.
      1913 webster

   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.
      1913 webster
see also:
in dust and ashes in sackcloth and ashes volcanic ashes volcanic ash 

Ash >> A Words
Ash, definition of term: Ash
ash_pag1.html

Ash Wednesday >> A Words
Ash Wednesday, definition of term: Ash Wednesday
ash+wednesday_pag1.html

Ash Tree >> A Words
Ash Tree, definition of term: Ash Tree
ash+tree_pag1.html