Definitions:
a 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.

an object, shape, or arrangement in the form of a pyramid

a system of financial growth achieved by a small initial investment, with subsequent investments being funded by using unrealized profits as collateral

stack or arrange in the shape of a pyramid.

achieve a substantial return on (money or property) after making a small initial investment