The Collaborative International Dictionary of English v.0.48:

Ember \Em"ber\, n. [OE. emmeres, emeres, AS. ?myrie; akin to
   Icel. eimyrja, Dan. emmer, MHG. eimere; cf. Icel. eimr vapor,
   smoke.]
   A lighted coal, smoldering amid ashes; -- used chiefly in the
   plural, to signify mingled coals and ashes; the smoldering
   remains of a fire. "He rakes hot embers." --Dryden.
   [1913 Webster]

         He takes a lighted ember out of the covered vessel.
                                                  --Colebrooke.
   [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Ember \Em"ber\, a. [OE. ymber, AS. ymbren, ymbryne, prop.,
   running around, circuit; ymbe around + ryne a running, fr.
   rinnan to run. See Amb-, and Run.]
   Making a circuit of the year of the seasons; recurring in
   each quarter of the year; as, ember fasts.
   [1913 Webster]

   Ember days (R. C. & Eng. Ch.), days set apart for fasting
      and prayer in each of the four seasons of the year. The
      Council of Placentia [A. D. 1095] appointed for ember days
      the Wednesday, Friday, and Saturday after the first Sunday
      in Lent, Whitsuntide, the 14th of September, and the 13th
      of December. The weeks in which these days fall are called
      ember weeks.
      [1913 Webster]

WordNet (r) 3.0 (2006):

ember
    n 1: a hot fragment of wood or coal that is left from a fire and
         is glowing or smoldering [syn: ember, coal]

Moby Thesaurus II by Grady Ward, 1.0:

35 Moby Thesaurus words for "ember":
   alluvion, alluvium, ash, brand, burning ember, cinder, clinker,
   coal, deposition, deposits, diluvium, draff, dregs, dross, feces,
   firebrand, froth, grounds, lees, live coal, loess, moraine,
   offscum, precipitate, precipitation, scoria, scum, sediment,
   settlings, silt, sinter, slag, smut, soot, sublimate