plural of pyramid scheme

(anatomy) A major collection of axons that transmits nerve impulses from the motor cortex to the spinal cord.

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

A pyramid-shaped roof.

(anatomy) A conical subdivision of the renal medulla

A corpus of ancient Egyptian funerary texts of the Old Kingdom consisting of spells to assist the journey of the dead king into the afterlife, carved on pyramid walls and sarcophagi.

An erosional remnant of a shield volcano and caldera, near Lord Howe Island in the Pacific Ocean.

A hoodoo (spire of rock).

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.

(mathematics) A number that represents the number of items in a pyramid having a given number of sides and layers