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.
      [1913 Webster]

            Jacob set a pillar upon her grave.    --Gen. xxxv.
                                                  20.
      [1913 Webster]

            The place . . . vast and proud,
            Supported by a hundred pillars stood. --Dryden.
      [1913 Webster]

   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.
      [1913 Webster]

            By day a cloud, by night a pillar of fire. --Milton.
      [1913 Webster]

   3. (R. C. Ch.) A portable ornamental column, formerly carried
      before a cardinal, as emblematic of his support to the
      church. [Obs.] --Skelton.
      [1913 Webster]

   4. (Man.) The center of the volta, ring, or manege ground,
      around which a horse turns.
      [1913 Webster]

   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.
      [1913 Webster]

The Collaborative International Dictionary of English v.0.48:

Stylite \Sty"lite\ (st[imac]"l[imac]t), n. [Gr. styli`ths, fr.
   sty^los a pillar.] (Eccl. Hist.)
   One of a sect of anchorites in the early church, who lived on
   the tops of pillars for the exercise of their patience; --
   called also pillarist and pillar saint.
   [1913 Webster]

         The two other holy men in Gregory's narrative had more
         exotic origins than the pair that has just been seen.
         Gregory encountered one of them when on a journey to
         the north-eastern parts of the Frankish kingdom. This
         was a Lombard, named Vulfolaic, who had spent some
         years in the arduous exercise of being a stylite, the
         Christian equivalent of a flagpole sitter; in other
         words, Vulfolaic was a monk whose main austerity
         consisted in living on top of a pillar. By carrying out
         this feat in the rain, snow, and frost of the Moselle
         valley, Vulfolaic had convinced the local population to
         overthrow and abandon the idol of Diana to which they
         were addicted.                           --Walter
                                                  Goffart,
                                                  FOREIGNERS IN
                                                  THE HISTORIES
                                                  OF GREGORY OF
                                                  TOURS
                                                  (http://www.arts.uwo.ca/florilegium/goffart.html).