noun the game of pool in which the balls are placed in the form of a triangle at spot.
2. pyramid ·add. ·noun the series of operations involved in pyramiding. ·see pyramid, ·vi.
3. pyramid ·add. ·vt to use, or to deal in, in a pyramiding transaction. ·see pyramid, ·vi.
4. pyramid ·noun a solid figure contained by a plane rectilineal figure as base and several triangles which have a common vertex and whose bases are sides of the base.
5. pyramid ·noun a solid body standing on a triangular, square, or polygonal base, and terminating in a point at the top; especially, a structure or edifice of this shape.
6. pyramid ·add. ·vi to enlarge one's holding or interest in a series of operations on a continued rise or decline by using the profits to buy or sell additional amounts on a margin, as where one buys on a 10% margin 100 shares of stock quoted at 100, holds it till it rises to 105, and then uses the paper profit to buy 50 shares more, ·etc. the series of operations constitutes a pyramid.