1. (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.

2. (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.

3. (n.) A portable ornamental column, formerly carried before a cardinal, as emblematic of his support to the church.

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

5. (a.) Having a support in the form of a pillar, instead of legs; as, a pillar drill.

antenna tower arcade arch atlas backbone baluster balustrade banister barbican barrel barrow base bedrock belfry bell tower bole boundary stone brass bust cairn campanile caryatid cask cenotaph champion colonnade colonnette colossus column cromlech cross cup cupola cyclolith cylinder cylindroid dado defender derrick die dolmen dome drum fire tower footstalk footstone foundation grave gravestone headstone hoarstone inscription jack lantern leader lighthouse mainstay marker martello martello tower mast mausoleum megalith memento memorial memorial arch memorial column memorial statue memorial stone menhir minaret monolith monument mound necrology newel-post obelisk obituary observation tower pagoda patron patroness pedestal pedicel peduncle peristyle pier pilaster pile piling pinnacle pipe plaque plinth pole portico post prize prop protector protectress pylon pyramid queen-post reliquary remembrance ribbon rock roll roller rostral column rouleau safekeeper shaft shrine sinews skyscraper socle spire staff stalk stanchion stand standard standpipe steeple stela stem stone stupa subbase supporter surbase tablet telamon television mast testimonial tomb tombstone tope tour tower tower of strength trophy trunk tube turret upholder upright water tower windmill tower worthy