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pyramidal

pyramidal is defined in Webster's Unabridged Dictionary (1913) with 2 senses. The full text of each entry is reproduced verbatim below.

Definitions

  1. 1.(Crystallog.) Same as Tetragonal. Pyramidal numbers (Math.), certain series of figurate numbers expressing the number of balls or points that may be arranged in the form of pyramids. Thus 1, 4, 10, 20, 35, etc., are trangular pyramidal numbers; and 1, 5, 14, 30, 55, etc., are square pyramidal numbers.
  2. 2.One of the carpal bones. See Cuneiform, n., 2 (b).

Source: Webster's Unabridged Dictionary, 1913 edition (public domain, via GCIDE / Project Gutenberg).

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