Definition of "pyramid" []

• A solid figure with a polygonal base and triangular faces that meet at a common point. (noun)
• Something shaped like this polyhedron. (noun)
• A massive monument of ancient Egypt having a rectangular base and four triangular faces culminating in a single apex, built over or around a crypt or tomb. (noun)
• Any of various similar constructions, especially a four-sided Mesoamerican temple having stepped sides and a flat top surmounted by chambers. (noun)
• The transactions involved in pyramiding stock. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "_First_, He laid down that the term pyramid was misapplied, as the term referred only to figures and structures of a special mathematical form; being apparently quite unaware that, as shown in the text and notes, pp. 219 and 220, it was often applied archæologically to sepulchral mounds and erections that were not faced, and which did not consist of a series of triangles meeting in an apex."
• "He notes that the late American psychologist Abraham Maslow never mentioned the word pyramid when writing about his "hierarchy of needs," but that shape has helped us to understand - to literally see - the concept."
• "Although the term "pyramid" may sound rather pejorative, it is true of all pension schemes."