pyramid

noun

• 1a monumental structure with a square or triangular base and sloping sides that meet in a point at the top, especially one built of stone as a royal tomb in ancient Egypt.

Pyramids were built as tombs for Egyptian pharaohs from the 3rd dynasty (circa 2649 bc) until circa 1640 bc. The early step pyramid, with several levels and a flat top, developed into the true pyramid, such as the three largest at Giza near Cairo ( the Pyramids, including the Great Pyramid of Cheops) which were one of the Seven Wonders of the World. Monuments of similar shape are associated with the Aztec and Maya civilizations of around 1200 bc- ad 750, and, like those in Egypt, were part of large ritual complexes

• 2an object, shape, or arrangement in the form of a pyramid:a pyramid of logs [as modifier]:a pyramid roof
• Geometry a polyhedron of which one face is a polygon of any number of sides, and the other faces are triangles with a common vertex:a three-sided pyramid
• Anatomy a structure of more or less pyramidal form, especially in the brain or the renal medulla.
• an organization or system that is structured with fewer people or things at each level as one approaches the top:the lowest strata of the social pyramid
• (pyramids) a game played on a billiard table with fifteen coloured balls arranged in a triangle and a cue ball.

• 3a system of financial growth achieved by a small initial investment, with subsequent investments being funded by using unrealized profits as collateral: the eventual collapse of illegal pyramids
• a form of investment in which each paying participant recruits two further participants, with returns being given to early participants using money contributed by later ones.

verb

• 1stack or arrange in the shape of a pyramid.

• 2achieve a substantial return on (money or property) after making a small initial investment: a bank can pyramid modest capital into an enormous sum of money