The Collaborative International Dictionary of English v.0.48:

Allegory \Al"le*go*ry\, n.; pl. Allegories. [L. allegoria, Gr.
   ?, description of one thing under the image of another; ?
   other + ? to speak in the assembly, harangue, ? place of
   assembly, fr. ? to assemble: cf. F. all['e]gorie.]
   1. A figurative sentence or discourse, in which the principal
      subject is described by another subject resembling it in
      its properties and circumstances. The real subject is thus
      kept out of view, and we are left to collect the
      intentions of the writer or speaker by the resemblance of
      the secondary to the primary subject.
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   2. Anything which represents by suggestive resemblance; an
      emblem.
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   3. (Paint. & Sculpt.) A figure representation which has a
      meaning beyond notion directly conveyed by the object
      painted or sculptured.
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   Syn: Metaphor; fable.

   Usage: Allegory, Parable. "An allegory differs both from
          fable and parable, in that the properties of persons
          are fictitiously represented as attached to things, to
          which they are as it were transferred. . . . A figure
          of Peace and Victory crowning some historical
          personage is an allegory. "I am the Vine, ye are the
          branches" [--John xv. 1-6] is a spoken allegory. In
          the parable there is no transference of properties.
          The parable of the sower [--Matt. xiii. 3-23]
          represents all things as according to their proper
          nature. In the allegory quoted above the properties of
          the vine and the relation of the branches are
          transferred to the person of Christ and His apostles
          and disciples." --C. J. Smith.
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   Note: An allegory is a prolonged metaphor. Bunyan's
         "Pilgrim's Progress" and Spenser's "Fa["e]rie Queene"
         are celebrated examples of the allegory.
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