The Collaborative International Dictionary of English v.0.48:

Pillar \Pil"lar\, n. [OE. pilerF. pilier, LL. pilare, pilarium,
   pilarius, fr. L. pila a pillar. See Pile a heap.]
   1. The general and popular term for a firm, upright,
      insulated support for a superstructure; a pier, column, or
      post; also, a column or shaft not supporting a
      superstructure, as one erected for a monument or an
      ornament.
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            Jacob set a pillar upon her grave.    --Gen. xxxv.
                                                  20.
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            The place . . . vast and proud,
            Supported by a hundred pillars stood. --Dryden.
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   2. Figuratively, that which resembles such a pillar in
      appearance, character, or office; a supporter or mainstay;
      as, the Pillars of Hercules; a pillar of the state. "You
      are a well-deserving pillar." --Shak.
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            By day a cloud, by night a pillar of fire. --Milton.
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   3. (R. C. Ch.) A portable ornamental column, formerly carried
      before a cardinal, as emblematic of his support to the
      church. [Obs.] --Skelton.
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   4. (Man.) The center of the volta, ring, or manege ground,
      around which a horse turns.
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   From pillar to post, hither and thither; to and fro; from
      one place or predicament to another; backward and forward.
      [Colloq.]

   Pillar saint. See Stylite.

   Pillars of the fauces. See Fauces, 1.
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