Transdeletion pyramid
（重定向自Transaddition）
A transdeletion pyramid (also called a transaddition pyramid or word pyramid when inverted) is a logological term for the triangular representation of a list of words in which each one is a scrambled form of the above word without one letter.
This seventeen-letter transdeletion pyramid, made of inferred words in an Unabridged Merriam-Webster dictionary, can be found in Ross Eckler's book Making the Alphabet Dance: