The Collaborative International Dictionary of English v.0.48:

Apple \Ap"ple\ ([a^]p"p'l), n. [OE. appel, eppel, AS. [ae]ppel,
   [ae]pl; akin to Fries. & D. appel, OHG, aphul, aphol, G.
   apfel, Icel. epli, Sw. [aum]ple, Dan. [ae]ble, Gael. ubhall,
   W. afal, Arm. aval, Lith. ob[*u]lys, Russ. iabloko; of
   unknown origin.]
   1. The fleshy pome or fruit of a rosaceous tree (Pyrus
      malus) cultivated in numberless varieties in the
      temperate zones.
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   Note: The European crab apple is supposed to be the original
         kind, from which all others have sprung.
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   2. (bot.) Any tree genus Pyrus which has the stalk sunken
      into the base of the fruit; an apple tree.
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   3. Any fruit or other vegetable production resembling, or
      supposed to resemble, the apple; as, apple of love, or
      love apple (a tomato), balsam apple, egg apple, oak apple.
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   4. Anything round like an apple; as, an apple of gold.
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   Note: Apple is used either adjectively or in combination; as,
         apple paper or apple-paper, apple-shaped, apple
         blossom, apple dumpling, apple pudding.
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   Apple blight, an aphid which injures apple trees. See
      Blight, n.

   Apple borer (Zool.), a coleopterous insect (Saperda
      candida or Saperda bivittata), the larva of which bores
      into the trunk of the apple tree and pear tree.

   Apple brandy, brandy made from apples.

   Apple butter, a sauce made of apples stewed down in cider.
      --Bartlett.

   Apple corer, an instrument for removing the cores from
      apples.

   Apple fly (Zool.), any dipterous insect, the larva of which
      burrows in apples. Apple flies belong to the genera
      Drosophila and Trypeta.

   Apple midge (Zool.) a small dipterous insect (Sciara
      mali), the larva of which bores in apples.

   Apple of the eye, the pupil.

   Apple of discord, a subject of contention and envy, so
      called from the mythological golden apple, inscribed "For
      the fairest," which was thrown into an assembly of the
      gods by Eris, the goddess of discord. It was contended for
      by Juno, Minerva, and Venus, and was adjudged to the
      latter.

   Apple of love, or Love apple, the tomato (Lycopersicum
      esculentum).

   Apple of Peru, a large coarse herb (Nicandra physaloides)
      bearing pale blue flowers, and a bladderlike fruit
      inclosing a dry berry.

   Apples of Sodom, a fruit described by ancient writers as
      externally of fair appearance but dissolving into smoke
      and ashes when plucked; Dead Sea apples. The name is often
      given to the fruit of Solanum Sodom[ae]um, a prickly
      shrub with fruit not unlike a small yellow tomato.

   Apple sauce, stewed apples. [U. S.]

   Apple snail or Apple shell (Zool.), a fresh-water,
      operculated, spiral shell of the genus Ampullaria.

   Apple tart, a tart containing apples.

   Apple tree, a tree which naturally bears apples. See
      Apple, 2.

   Apple wine, cider.

   Apple worm (Zool.), the larva of a small moth (Carpocapsa
      pomonella) which burrows in the interior of apples. See
      Codling moth.

   Dead Sea Apple.
      (a) pl. Apples of Sodom. Also Fig. "To seek the Dead Sea
          apples of politics." --S. B. Griffin.
      (b) A kind of gallnut coming from Arabia. See Gallnut.
          [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Discord \Dis"cord`\, n. [OE. discord, descord, OF. discorde,
   descorde, F. discorde, from L. discordia, fr. discors,
   -cordis, discordant, disagreeable; dis- + cor, cordis, heart;
   cf. F. discord, n., and OF. descorder, discorder, F.
   discorder, to discord, L. discordare, from discors. See
   Heart, and cf. Discord, v. i.]
   1. Want of concord or agreement; absence of unity or harmony
      in sentiment or action; variance leading to contention and
      strife; disagreement; -- applied to persons or to things,
      and to thoughts, feelings, or purposes.
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            A false witness that speaketh lies, and he that
            soweth discord among brethren.        --Prov. vi.
                                                  19.
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            Peace to arise out of universal discord fomented in
            all parts of the empire.              --Burke.
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   2. (Mus.) Union of musical sounds which strikes the ear
      harshly or disagreeably, owing to the incommensurability
      of the vibrations which they produce; want of musical
      concord or harmony; a chord demanding resolution into a
      concord.
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            For a discord itself is but a harshness of divers
            sounds m???ing.                       --Bacon.
      [1913 Webster]

   Apple of discord. See under Apple.

   Syn: Variance; difference; opposition; contrariety; clashing;
        dissension; contention; strife; disagreement;
        dissonance.
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WordNet (r) 3.0 (2006):

apple of discord
    n 1: (classical mythology) a golden apple thrown into a banquet
         of the gods by Eris (goddess of discord--who had not been
         invited); the apple had `for the fairest' written on it and
         Hera and Athena and Aphrodite all claimed it; when Paris
         (prince of Troy) awarded it to Aphrodite it began a chain
         of events that led to the Trojan War