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.

Jacob set a pillar upon her grave.
Gen. xxxv. 20.

The place . . . vast and proud,
Supported by a hundred pillars stood.

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.

By day a cloud, by night a pillar of fire.

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

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

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.

Pil"lar, a. (Mach.) Having a support in the form of a pillar, instead of legs; as, a pillar drill.