(1):
(a.) Having a support in the form of a pillar, instead of legs; as, a pillar drill.
(2):
(n.) 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.
(3):
(n.) 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.
(4):
(n.) A portable ornamental column, formerly carried before a cardinal, as emblematic of his support to the church.
(5):
(n.) The center of the volta, ring, or manege ground, around which a horse turns.