An illicit money-making investment scheme whereby early investors are paid primarily or wholly by later investors. Eventually all such schemes fail to the detriment of recent (later) investors.

plural of pyramid scheme

(geometry) A three-dimensional geometric figure with a square base and four triangular sides that connect at one point. An example is the Great Pyramid of Giza.

A three-dimensional figure with four triangular bases.

plural of square pyramid

plural of triangular pyramid

A tower made of people standing or kneeling on top of each other. / (circus) A formation of triangular shape with one or a small number of performers supporting a large number of other performers.

A pyramid-shaped diagram in layers, where each layer represents a group of animals that feeds on the layer below.

A diagram that shows the relative amounts of energy or matter, or numbers of organisms within each trophic level in a food chain or food web.

plural of step pyramid