n. 1 a a usu. slender vertical structure of wood, metal, or esp. stone used as a support for a roof etc. b a similar structure used for ornament. c a post supporting a structure. 2 a person regarded as a mainstay or support (a pillar of the faith; a pillar of strength). 3 an upright mass of air, water, rock, etc. (pillar of salt). 4 a solid mass of coal etc. left to support the roof of a mine. from pillar to post (driven etc.) from one place to another; to and fro. pillar-box Brit. a public postbox shaped like a pillar. pillar-box red a bright red colour, as of pillar-boxes. Pillars of Hercules 1 two rocks on either side of the Strait of Gibraltar. 2 the ultimate limit. pillared adj. pillaret n.
[ ME & AF piler, OF pilier ult. f. L pila pillar ]