pyramid

I. noun Etymology: Latin pyramid-, pyramis, from Greek Date: 1549 1. a. an ancient massive structure found especially in Egypt having typically a square ground plan, outside walls in the form of four triangles that meet in a point at the top, and inner sepulchral chambers b. a structure or object of similar form 2. a polyhedron having for its base a polygon and for faces triangles with a common vertex — see volume table 3. a crystalline form each face of which intersects the vertical axis and either two lateral axes or in the tetragonal system one lateral axis 4. an anatomical structure resembling a pyramid: as a. any of the conical masses that project from the renal medulla into the kidney pelvis b. either of two large bundles of motor fibers from the cerebral cortex that reach the medulla oblongata and are continuous with the pyramidal tracts of the spinal cord 5. an immaterial structure built on a broad supporting base and narrowing gradually to an apex <

the socioeconomic pyramid

> • pyramidal adjective • pyramidally adverb • pyramidical adjective II. verb Date: circa 1900 intransitive verb 1. to speculate (as on a security or commodity exchange) by using paper profits as margin for additional transactions 2. to increase rapidly and progressively step by step on a broad base transitive verb 1. to arrange or build up as if on the base of a pyramid 2. to use (as profits) in speculative pyramiding 3. to increase the impact of (as a tax assessed at the production level) on the ultimate consumer by treating as a cost subject to markup